calimaero® 4 Inch Backdraft Exhaust Damper Seal One Size Fits All Duct Backdraft Damper Gravity Powered Made in Germany HVAC Damper Dryer Vent Valve Keep Cold Air Out

I needed this at the end of a 20 foot run of flexible duct. It fit perfectly in the 4 inch plastic flange I installed in the wall. I agree with other reviews that the plastic bar holding the rubber flap in place is pretty flimsy. I used some Loctite Fun-Tak Mounting Tabs to secure it. The manufacturer should have used a stainless steel spring instead of the plastic bar. The damper works great for me. 105 CFM bathroom fan pushes the rubber flaps open easily and absolutely no backdraft when the fan is off. I will buy this again.

I was a little skeptical of the mechanism but was lured by the thin dimensions. The product I received is basically junk. It is not as pictured. The flapper is not black plastic or rubber, but rather this light brown, very thin, very flimsy rubber. It doesn't have enough stiffness to even overcome gravity if the flapper is facing downward, and when facing upward the flap doesn't sit flat (I tried adjusting it a bit, as it's just friction-fit in place, but it is just too thin and cannot be made to sit flat).I don't consider this the same product pictured, and this substitute does not even function.

Worked simply and functional.

I was looking for a back flow preventer with minimal pressure drop that would seal tightly. I live in a condo with an ducted exhaust that sometimes has reversals that can bring smoke or odors into out unit. Out of the box the flapper was puckered but I was able to cut small notches to allow it to lay flat.life is compromise an I could not mount vertical because the weight of the flapper made it open and I was afraid it would not close for minor reversals. I was able to install it horizontal which appears to work pretty good.

Update: went from 5 stars to 1 star. The flexible plastic that’s designed to seal has warped after one year. It needs a new flap, but I have no way to get one.I originally bought this because the exhaust from the microwave had a metal exhaust trim with a flapper that would make noise nonstop on windy days.I removed the metal flap and placed this in its place. It works perfect for that. I’ve had it installed for about 1.5 years at this point.Although it is thin and doesn’t feel commercial, it does what it’s designed to do. I’d pay a little extra for something stronger, but then again it isn’t exerted to any extreme wind speeds from the house. They are made from a plastic (PVC?) skeleton and it has a thin rubber flap.I since purchased another 2 to place on the other exhausts from bathrooms. They work perfect for this application.

Excellent product If you can’t fit a typical damper in old construction, flexible duct work (or dont have full access). This was exactly what I needed! It’s only 1/2 thick so you can wedge it right into the exposed duct without having to tear everything out.

This damper broke when I used my bathroom fan, I had to replace it instantly.

Does not work. The rubber flap is like paper and does not close after vent. The brace that holds the rubber flap on is not sturdy and falls off. When air is flowing through vent the rubber flap flies off and out the vent tube.

We have a half bath in our house(built 2017) that was always cold. I've checked the insulation, wi dows seals, and even upgraded the heat run fron a 4" to a 5". Nothing seamed to improve the temperature in the room. I i stalled this damper i. The ventilation fan and within minutes the room was as warm as the rest of the house. Its currently -30°c here and the room is warm. 10/10 will install in every bathroom from now on.

CE TRUC EMPECHE VRAIMENT LE VENT DE PASSER DANS LA HOTTE ,j'ai du faire un réducteur en impression 3d car mon tuyau etait plus gros

It does what it is supposed to, rare these days. Others have said it was too small, so either there was a duff batch previously or their pipe wasn't 100mm, (4 inches). The silicone membrane also laid mainly flat, but it is possible to gently smooth it out from where it is gripped by the central bar as you can see, it lies perfectly flat, it is not intended for insulation, just to stop the draughts, and be light enough to open when the fan is on. Mine fitted snuggly in a100mm pipe,the rubber fin gasket compressing to seal. Due to the poor original fitting of the pipe, I then discovered air going around it between the wall and pipe, coming into the room thru the fan casing. It is therefore worth sealing inside and out if accessible, to ensure no gap between pipe and brickwork, before condemnation of the product! My wall faces north across a field,and the shutter has stopped the wind rotating the fan in reverse, thus preventing a cold draught in the bathroom. It has proven silent in operating thus far.

In contrast to other reviewers, mine seemed to fit just fine into a 100mm galvanized spiral duct.The flap is made of a very flexible type rubber, meaning it opens with very low fan pressure. The housing is made of ABS plastics. The flap does has a tendency to crease if not fitted properly inside its retaining bracket, so do take notice and flatten it out before installing.All considered i'm satisfied with its functionality. The price could have been a tad lower though. Also a 125mm model would be nice to have.

Montei no tubo do exaustor para evitar o refluxo de gases do esquentador para o exaustor e resolveu-me o problema