The Best Recirculating Range Hood With Charcoal Filters: Reviewed and Compared


Last Updated: 13th March 2018

Ductless range hood, also commonly known as recirculating range hoods or ventless range hoods are similar in construction to regular ducted range hoods. The only difference is that they are stand-alone systems which do not need to be connected to exterior ductwork. They are ideal for people living in apartments, rented homes or just about anyone who would have problems creating vents for some reason or another. Maybe, you just don't want to go through the extra trouble or prefer to have a ductless system since they are usually quieter?

I've picked the best based on reviews, volumes sold and most wished for products on the most popular retailer websites for range hoods, namely: Amazon, Ebay and A J Madison. This list is manually updated multiple times a year. Since this page is really long containing product comparison tables, followed by detailed reviews and pictures of the best hoods and more, it is recommend you use the navigation below to go to the section you're interested in. I hope I can help you find the perfect hood for your home. Don't hesitate to contact me for queries unanswered on this page.

  1. Comparison: Best Ductless Under Cabinet Range Hoods
  2. Comparison: Best Ductless Wall Mount Range Hoods
  3. Comparison: Best Ductless Island Range Hoods

Below the comparison tables, you'd find a general overview of the product, it's top features, problems you could come across during it's installation and working life. Also, as an added bonus, towards the end of each review is included a list of conditions under which I would personally buy the particular range hood.

Just in case you're not really sure if a recirculating range hood is the best choice for your home we've got you covered with a lot of useful information and guides towards the end of this page:

  1. What Are Ductless Range Hoods?
  2. When Is It Wise to Buy a Ductless Range Hood?
  3. Guide on Picking the Best Ductless Range Hood

The Best Under Cabinet Ductless Range Hoods

  • Average Rating
  • Dimensions
  • Minimum Height Above Cooktop
  • CFM
  • Speeds
  • Lighting
  • Controls
  • Sound
  • Grease Filters
  • Charcoal Filters
  • Electrical Connection
  • Delay Shut Off
  • Warranty Info
  • Color Options
  • Made in
  • Buy on Amazon
  • Other Stores
    • Cosmo Rating
    • 29.5" X 18.9" X 4.92"
    • Not specific recommendation
    • 250
    • 3 speeds
    • 2 Watt LED lighting sufficient for illuminating the stove but these are not stand alone lights for your entire counter-top (some people expect this)
    • 5 electronic push button controls
    • Maximum sound level of 60 dB
    • Two dishwasher safe, quick release aluminum multi-layer mesh grease filters
    • Ductless compatible charcoal filters must be separately bought
    • Designed for a hardwire installation, you'd have to buy a plug if you want to plug it in.
    • No
    • 5 year limited warranty. Their customer team is based in the US. For questions, the seller can be contacted via Amazon or called at: 1-888-298-8144
    • Stainless steel
    • Manufactured in China and shipped to California
    • Check Current Price
    • Walmart
    • Broan rating
    • 30" X 20" X 7.2"
    • No specific recommendation
    • 220
    • 2 speeds
    • 2 level light settings and two bulbs (not included). Based on customer feedback for a mix of longevity, efficiency and brightness it is recommended to use PAR20 LED bulbs or specifically these Triangle Bulbs
    • Flush mounted rocker controls. 3 way rocker switch for the light (high, low, off) and 3 way for the fan too (high, low, off)
    • Low speed, 1.5 sones which is usually less noise than the sound of your food simmering in a pot and 4 sones at high speed
    • Two dishwasher safe aluminum grease filters.
    • Charcoal filters for ductless operation are not included. They can be bought separately.
    • Designed for a hard wire installation, you can buy a plug if that's what you want.
    • No
    • We recommend you read page six of this document or contact Broan support
    • On Amazon: Bisque, Black, Off-White, Stainless Steel and White
    • Manufactured and assembled in China
    • Check Current Price
    • AJ Madison
      Appliances Connection
    • GE rating
    • 32.5" X 23.6" X 8"
    • No specific recommendation
    • 300
    • 4 speeds
    • Dual halogen lights: On, off, night light
    • Electronic backlit controls. This model also includes an optional remote control that can control the fan and lights from anywhere in the kitchen (Sold separately).
    • 1.5 sones at low speed (120 CFM), 2.2 at medium speed (180 CFM), 3.0 at high speed (230 CFM) and 6.5 at boost speed (300 CFM)
    • Grease filters are easy to remove and dishwasher safe
    • Charcoal filters needed for ductless installation are sold separately.
    • The product must be hardwired, a cord kit can be bought separately
    • Delay shut off option of 15 minutes
    • Limited one year parts and labor warranty
    • On AJ Madison: Black, Slate, Stainless Steel, White
    • Check Current Price
    • AJ Madison
      Appliances Connection

Top Ductless Wall Mount Range Hoods



Akdy 30 Wall Mount Range HoodAkdy AZ-63175S 30"
Akdy wall mount range hood reviews
  • 760 CFM Pros
  • ETL Safety Approval: US and Canada
  • Convertible Pros
  • Telescopic Chimney 8'-8.5' Ceilings
  • 2 LED lighting at the back
  • Touch Controls Pros
  • Specs say: Noise less than 65db
    (Reality: Loud Operation)
  • Charcoal Filters: Not Included
  • Plug-in (Not Hardwire)
  • Vent diameter: 6" Pros
  • 3 Year Parts Warranty Pros
  • -
  • Dishwasher Safe Anodized Aluminum Filters
  • 3 speed fan
Kitchen Bath Collection 30 Wall Mount Range HoodKitchen Bath Collection STL75-LED 30" and 36"
Kitchen Bath Collection wall mount range hood reviews
  • 412 CFM
  • Convertible Pros
  • Adjustable Chimney: Max 41" Pros
  • 2 High End LED Lighting: 49 bulbs each (On the front)Pros
  • Touch Controls Pros
  • Noise between 48db (min speed) and 58db (max speed) Pros
  • Charcoal Filters: Included Pros
  • Plug-in (Not Hardwire)
  • Vent diameter: 6" Pros
  • 1 Year manufactures defect Warranty
  • -
  • Aluminum micro-cell grease filters
  • 3 speed fan
  • Read Reviews Kitchen Bath Collection Wall Mount Range Hood
  • Questions Answered Kitchen Bath Collection Wall Mount Range Hood
Z Line ZLKB36 Wall Mount Range HoodZ Line ZLKB 36"
Z Line ZLKB36 wall mount range hood reviews
  • 760 CFM Pros
  • CE, GS, CCC Safety Approval: US and Canada Pros
  • Convertible Pros
  • Adjustable Chimney: Max 40"
  • 2 20W Halogen Lights: Movable (At the back) Pros
  • Touch Controls Pros
  • -
  • Charcoal Filters: Cost Extra
  • Plug-in (Not Hardwire)
  • Vent diameter: 6" Pros
  • 1 Year parts warranty
  • Auto Shut Off Pros
  • Stainless Steel dishwasher safe baffle filters
  • 4 speed fan Pros
  • Read Reviews Z Line ZLKB36
  • Questions Answered on the Z Line ZLKB36



Model 1: The Akdy AZ63175S

With a maximum suction power of 400 CFM, this range hood has a sufficient exhaust capacity for most homes. Perfect for home use, it can be operated at three different speeds: low, medium and high.

A quick view of what you can expect. The one on the left includes an extension chimney bought from the Akdy website.

What Makes It One of the Best

  1. High-quality stainless steel construction
  2. Teflon coated blades prevent rusting and increase the product lifespan.
  3. An adjustable chimney allows you to adjust for multiple heights easily.
  4. 3 years warranty on major parts.
  5. Amazing customer support.
  6. It is easy to obtain replacement parts from customer support.
  7. Aesthetics: most people take a look at it and assume that it's an expensive model.
  8. Superb price and value for money.

Replacing an Existing Range Hood

Installing the AKDY AZ63175S
Before installation. Here, an under cabinet range hood was replaced by the Akdy AZ63175S
AKDY AZ63175S after installation
A perfect fit after installation.

Features I Do Not like About It

  1. Horrible installation instructions, but it's easy enough and there are plenty of YouTube videos from other brands.
  2. A rather loud beep when operating the light, timer and speed options.
  3. Lighting could be better, I'd not solely depend on it to light up my cooktop.
  4. Do not blindly trust the time displayed, you may end up late for work. It's sometimes off by a minute each hour. This is a massive 24 minutes each day.

Weak LED Lights

AKDY AZ63175S weak LED lights
The lights are really weak. However, the manual suggests that the bulbs should not be changed to a higher wattage.
AKDY AZ63175S lights may not be bright enough
The lights are not bright enough to even counter the shadow produced by overhead lights. Therefore, you should not solely depend on the range hood lighting while you cook.

I Would Buy It, If:

  1. I was ducting to the outside.
  2. I usually do not cook greasy food, as the fan at the highest speed is 65db loud.
  3. I did not depend on my range hood for all the lighting on my cooktop.
  4. I was looking for longevity and good customer support.
  5. I had a relatively low budget.
  6. I want a range hood that looks expensive.

You could check out other reviews and buy this range hood on Amazon. Chimney extensions, if required, can be bought from the AKDY website. However, from reading reviews online, it's better to contact AKDY via their Amazon page and ask them to ship you an extension along with the range hood (you will have to pay additionally for this). If you want to know more about AKDY as a company, the quality of their customer service and check out other models they sell, check out our AKDY range hood reviews.

Check Price and Buy on Amazon

Other Specifications

 Weight  21.6 pounds
 Dimensions  18.9" X 30" X 41.7"
 Circulation Type  Ducted & Recirculating
 Manufactured In  USA
 Connection type  Plug-in
 Telescopic chimney  For 8 to 8.5-foot ceilings (can be extended)
 Noise  65 dB
 Ducting inner diameter  6"
 Motor power  170W

Model 2: The Kitchen Bath Collecton STL75-LED

With a maximum CFM of 412, the KBC STL75 also operates at three different speeds. What I personally love is not just the range hood, but the company behind it with their policy of putting the customer first.

The kitchen bath collection STL75 installed in a home.

Just like the AKDY model we've seen, this too has two LED bulbs. In the past, the bulbs were placed at the back of the range, but after listening to customers they've moved the lights to the front which greatly increases cooktop luminence.

If you look into the product specifications, it clearly states that it is your responsibility to ensure that a 412 CFM range hood is sufficient for your cooktop and that you should calculate your CFM requirements before you buy it. This isn't just a nice gesture, failure to do so may void your warranty.

An amazing setup of the KBC STL75-LED
If you're good at metal working, you can easily cut the chimney to make the range hood fit in the available space.

What Makes It One of the Best

  1. 49 tiny LED bulbs on each of the front lights. This is bright, maybe too bright.
  2. Very silent operation even at the highest speed (max sound level of 58db).
  3. The charcoal filters are included in the pack, this could be a pro or a con depending on whether you're installing it ductless or ducted. Maybe, they should make it an accessory and further decrease the price of the base model.
  4. The model as a whole is constructed from 304 stainless steel which is corrosion resistant.
  5. Aluminum micro cell grease filters are very efficient when it comes to trapping grease and fumes, this is a very important feature if you're installing as a recirculating range hood. The grease filter is also dishwasher friendly.
  6. The adjustable telescopic chimney is not only easy to adjust, but it has no visible weld seams on either of the three sides, which is a plus considering aesthetics.
  7. A flexible aluminum duct is included.
  8. Delayed shut off is a default setting. The first power off touch activates the delayed shutoff, another tap and it's switched off instantly.
  9. 1-year manufacturers defect warranty. Note that use of the product with an incompatible stove, one that would require a higher CFM could void your warranty.

A View of the LED Lights and How They Function in a Kitchen

LED Bulbs STL75
49 LED bulbs make up each of the two front lights.
Bright illumination KBC STL75
A view of the range hood installed in a kitchen and a close up of how well it illuminates the cook top.

Listen to the Fan and the Beeps - by KBC

Features I Do Not like About It

  1. The lights are extremely bright and can be straight in the eyes of someone who isn't tall. Unfortunately, there is no dimmer option nor a way to direct them to the rear.
  2. You may need more mounting brackets than what you're provided with. The range hood does remain attached to the wall with what's given, but personally, I'd use extra mounting brackets available at any local store to fasten it firmly to the wall. Without the extra brackets, the hood tends to vibrate when in the highest mode of operation.
  3. The touch sensor to turn the light on and off has a rather loud beep.

The Fan, Lights and Controls in Operation


I Would Buy It, If:

  1. I was installing it as a recirculating model because installing this model as a ducted range hood is a bit harder than one would imagine especially true if you are replacing an existing hood with existing ductwork.
  2. I needed a bright cooktop.
  3. I was looking for a range hood that operates well for at least 6-7 years, if not more.
  4. I needed a blower that absorbs/exhausts smell and fumes right out of my kitchen.
  5. I had a relatively low budget.
  6. I wanted a range hood that looks classy.
  7. Customer support was important to me.

You can check out commonly asked questions, read other reviews and buy this range hood at Amazon. If you have any questions, you can contact them via their amazon sellers page and they usually get back to you in under 24 hours.

Check Price and Buy on Amazon

Model 3: The Z-Line ZLKB-36

Around $150 - 200 more than the previous two models, this model still makes my list because at the end of the day it's a lot cheaper than the other "well-renowned" brands on the market, while at the same time solves a lot of problems we've come across with the AKDY and KBC range hoods.

Z-Line ZLKB-36
The Z-Line ZLKB36 in a modern kitchen.

For instance, the Akdy lights were too dim whereas the KBC range hood lights were too bright and right into the eyes of some. But with this Z-Line range hood, you have 2 halogen lights at the back, which can be titled to light up the cooktop as you see fit.

The manufacturers do not specify the exact sound level in decibel. But being a 760 CFM range hood capable of operating at 4 speeds one would expect it to get really noisy, considering the fact that it's not an expensive model. However, you're rarely going to need to operate at the highest speed.

Even when standing close to the range hood, you don't have to raise your voice when in operation up to speed 3. But at speed 4 it gets kind of loud and you're going to have to slightly raise your voice.

The Z-Line ZLKB-36 as the focal point of your kitchen
The range hood is the focal point of this kitchen.

What Makes It One of the Best

  1. A 760 CFM motor which makes it powerful enough for all homes.
  2. The two lights even though placed at the back of the range hood can easily be tilted to ensure the cooktop is lit as required.
  3. Push buttons with LED indicators instead of touch controls. Most people prefer to use push buttons because this is what they are used to on long lasting appliances. I'm in the same boat here and cannot argue otherwise.
  4. The default chimney extends within the limits of 26.3 inches to 40 inches.
  5. Easily available telescopic chimney extension that allows installation in homes with up to 12-foot ceilings.
  6. Plug and play setup. The fans and motor are already assembled, all you need to do is join the pieces of the puzzle while you mount the hood.
  7. It's got a delayed shut-off feature (3 minutes).
  8. The best packaging among the three reviewed here, it has a protective layer on the stainless steel components. You can either peel it off before installation or once the hood is installed, which is definitely the better route. Getting the protective layer off the baffles is a bit tricky, you may need to use a blade and snip at it a bit.
  9. It's got a good 1 year parts warranty and you can read more about it here.
The Z-Line ZLKB-36 has bright halogen bulbs
The original halogen lights are sufficiently bright to light up the cooktop.

Features I Do Not like About It

  1. It may be a personal choice, but LED's would be better than Halogens.
  2. The plastic duct that is shipped along with the range hood is a joke, you're better off buying a metal flex tube from your local hardware store (some localities even require you to have a metal tube). It's not necessarily a con because metal flex tubing is cheap.
  3. The mounting wall screws are not strong in my opinion and you're also going to need more than what they provide. You could definitely use the ones that they have included, but you're better off getting a few more just to be on the safe side.
  4. The baffle filters are not securely fit in place. The only reason I would do this when designing baffle filters myself is to make sure that they do not bend over years of use on high suction. If the filters are not firmly attached they have the freedom to move and prevent distortion (to some extent). If you wish, you could easily fix this issue with some simple DIY hacks.

I Would Buy It, If:

  1. I often fry stakes or fish that results in a lot of fumes, as that's when I could use a motor with a strong CFM. But in general when searing meats you won't need to go above level 3.
  2. I need good suction even at low speeds with low noise levels.
  3. I intend to use the inbuilt range hood light to brighten up my cooktop.
  4. I was looking for a model that is very simple to install.
  5. I need a model that plugs into a socket.
  6. Longevity is an important feature to me.
  7. I am looking for customer service personnel that are easy to interact with.
The ZLKB36 viewed from two different angles.
The ZLKB36 viewed from two different angles.

You can check out commonly asked questions, read other reviews and buy this range hood at Amazon. This model does fluctuate in prices very often and you could end up saving $50 if you buy it at the right time. Therefore, before you buy it, make sure that you take a look at a price tracker (a simple google search to find one) to see if the current listing is a good price.

Check Price and Buy on Amazon

Check out these two Wall Mount Range Hoods which are rising up the rankings real quick, they look promising and 2018 may see them move into my top three list. If you don't see them, you may have to disable Adblock for this site.


Island Ductless Range Hood




Eureka 30 Inch Island Mount Range HoodEureka European Style 30"
Eureka European Style Island Mount Range Hood Review
  • 900 CFM Pros
  • -
  • Convertible Pros
  • Carbon Filters Sold Seperately
  • Chimney adjusts for ceilings from 8' to 9'
  • -
  • 4, 20W Halogen Bulbs
  • 3 Speed Push Control Panel
  • Noise Level: 30dB (lowest speed) and 56dB (highest speed) Pros
  • Vent Diameter: 6"
  • Back Draft Damper present Pros
  • Anodized Aluminum Filters - Dishwasher Safe
  • -
  • 3 Year Limited Parts Warranty
  • Read Reviews Eureka 30 Inch Island Mount Range Hood
  • Questions Answered Eureka 30 Inch Island Mount Range Hood
Akdy AZ-B02-IS-90Akdy AZ-B02-IS-90 36"
Akdy AZ-B02-IS-90 Island Mount range hood reviews
  • 870 CFM
  • ETL Safety Approval: US and Canada Pros
  • Convertible
  • Carbon Filters Sold Seperately
  • Required Ceiling Height: 8' to 9'
  • Additional Chimney Extension Sold Seperately Pros
  • 4, 35W Halogen Bulbs Pros
  • Dual Touch Panel (3 speed) + Remote Control Pros
  • Less than 65dB at the highest speed
  • Vent Diameter: 6'
  • -
  • Stainless Steel Baffle Filter - Dishwasher Safe
  • Timer for Delayed Shut Off Pros
  • 3 Year Limited Parts Warranty
  • Read Reviews Akdy AZ-B02-IS-90
  • Questions Answered Akdy AZ-B02-IS-90
Golden Vantage GVAI-30CF Island Mount Range HoodGolden Vantage GVAI-30CF 30"
Golden Vantage GVAI-30CF Island Mount Range hood reviews
  • 840 CFM
  • ETL Safety Approval: US and Canada Pros
  • Convertible Pros
  • Charcoal Filters Sold Seperately
  • Telescopic Chimney for 8' to 9' Ceilings
  • -
  • 4, 2W LED Lights
  • 3 Speed Push Control Panel
  • Less than 65dB at the highest speed
  • Vent Diameter: 6"
  • Non Return Air Flap Pros
  • Aluminum Grease Filter - Dishwasher Safe
  • Auto Shut Off: Programmable 1 minute Pros
  • 3 Year Limited Parts Warranty
  • Read Reviews Golden Vantage GVAI-30CF Island Mount Range Hood
  • Questions Answered on the Golden Vantage GVAI-30CF Island Mount Range Hood






What are Ductless Range Hoods?

A recirculating hood just as the name suggests, is one that doesn't exhaust air outdoors or to an Attic/Basement (with open windows of course). Instead, it just recirculates the air around your kitchen. The stale/polluted air is passed through charcoal filters which purify it by getting rid of all fumes, odor and any kind of smoke that's emitted while you cook.

Why choose Recirculating Range Hoods?

There are plenty of reasons why people would opt for ductless range hoods rather than their ducted counterparts. Some of the reasons could be:

  1. Ductless Hoods are cheaper – Short term costs (No duct installation charges, but you do have to pay for charcoal filter replacements).
  2. Energy efficient – They don't have to be very high CFM so as to throw the air through the duct out to the exit.
  3. During the winters when you'eturned on your heaters you wouldn't want the warm air escaping from your kitchen through the ducts. Backdraft dampers help when not in use, but when in use you're going to be sending out warm air from your home.
  4. Perfect for remodeling where you do not want to install vents

Guide on picking the best Non-Ducted range hood for your kitchen

When picking a range hood for your kitchen there are quite a few factors to consider. Among the many, we've decided to focus on the major aspects:

What's your budget?

Let's be frank. There are hundreds of models to choose from and you're going to want to create a shortlist. One of the best ways to get rid of a huge chunk of the pie is by deciding on your budget. Make a wise decision here. Range hoods are rather large investments and are going to be with you for years, so don't be stingy and get a horrible one. If you're short on funds, it would be wiser to save up for a few more months before you take the plunge.

What kind of filter do you prefer?

There are three kinds of filters that are used in recirculating range hoods:

  1. Charcoal Filters
  2. Baffle Filters
  3. Mesh Filters

Charcoal Filters

They are going to be needed in all recirculating kitchen hoods as they are responsible for getting rid of odor and absorption of fumes, etc. You have no choice here. You do have a choice when it comes to the other two though. Charcoal filters need to be replaced and the other one either Baffle or Mesh doesn't have to as long as you maintain it well.

Baffle Filters

Usually manufactured of Aluminum or Stainless Steel and in some cases mild steel, they work by forcing the greasy air to pass through them haphazardly, quickly changing direction as it rises. However, grease being heavier (more viscous) than air, it cannot change direction as quickly as the air which results in it collecting on the baffles. From here it trickles down and collects in a tray that needs to be cleaned every few months or so. They can be quite large and not fit in dishwashers at times and are also more expensive than mesh filters.

Mesh Filters

Mesh filters are basically a group of many fine metal mesh layers placed one behind another. The greasy air is passed through them and it collects on the minute pores as it passes through. Here too, there's a tray that collects the grease. However, the grease tends to clog the pores a lot easier in this case and you would have to clean the filters every other week. On a positive note, range hoods with these filters are usually a bit cheaper.


It goes without saying that you're going to want your range hood to look good and probably enhance the looks of your kitchen. There are plenty of models to choose from, and they usually come in different styles. There are plenty of similar models that only look different, so you don't have anything to worry about in this regard.

CFM power of the recirculating hood

CFM (Cubic Feet per Minute) is the measure of power of your range hood. The ideal CFM that you require would be based on various factors such as the size of your kitchen, the volume of food you cook, the kind of food you cook, the length of the ducting, the number of burners and more. It's a complicated calculating process and that's why we've built an online calculator for you. Check out our kitchen hood CFM calculator.

The CFM determines how long it takes for all the air in your kitchen to pass through the range hood. An ideal CFM for most homes would be around 300.


Every range hood produces noise when the motor and fan run. However, some of them are louder than the comfort threshold and can turn out to be a real annoyance in the kitchen. Therefore when picking your range hood make sure that you take a look at the noise level. For home use the ideal sound level would be around 4 sones or a bit higher as that's the level of regular human conversations.

Check for size before you buy

A new addition to the list, we've added this because we had a few people contacting us asking us if we knew where they could get extensions for their Wall and Island mount hoods. Before you place an order you need to measure the area over your cooking range. The ideal range hood covers all your burners, if not the entire cooking range.

If you've got a cooking range with 4 burners, you should make sure that the range hood moves far back to cover the back ones completely and at least a small percentage of the front burners. Check the height of the cooking range from the spot where you intend to place the recirculating range hood. Keep it high enough to be no hindrance to you while you cook but not too high as it would lead to a larger probability of fumes escaping the hood.

Additional Features

With the increase in the number of features of your recirculating kitchen hood, the price is going to rise as well. But, if you're looking for the best, you should try and find range hoods with the following features too:

  1. Lighting - Most range hoods have halogen or LED lighting and have a low and bright version which can be used as per the need
  2. Fan Speeds - The more fan speeds the better as then you would be able to adjust it to exactly what you need, there's no waste of electricity this way.
  3. Auto Switch-Off - Not many recirculating range hoods come with this feature. Basically you can set a time wherein the range hood switches off on it's own after your set time.
  4. Heat Sensors - Some models also have heat sensors that are capable of increasing and decreasing the fan speed as needed based on the amount of heat they detect in your kitchen.


The Final Say - Should you proceed with a Recirculating range hood?

One of the main reasons as to why people choose recirculating range hoods is because they're cheaper and you also save on the installation of ducts.  This is a wise choice for many as the savings would allow them to buy a range hood with better features. But, if you're looking for efficiency it's always better to buy a cheaper hood and install ducting as this would save you on your power bills too. However, if ducting is completely out of the question you should buy a recirculating hood keeping in mind the air flow rate, noise and of course - the filtration!