calimaero® Seal Backflow Valve DN 100 mm Internal Check Valve Made of Recycled Plastic, Quiet Rubber Flaps, Universal Use in Aluminium Flex, PVC, Sheet Metal, KG, HG Exhaust Pipes

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.

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.

Funziona bene: l'ho usata come seconda valvola inserita nel tubo dell'aspiratore, dal quale proveniva cattivo odore in caso di vento: ho dovuto solo aggiungere un pezzo di plastica per evitare il ritorno delle ali di gomma della valvola, e l'ho inoltre aumentata di diametro (esterno) con alcuni giri di nastro isolante. Ottimo acquisto.

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.