Repa Market 4" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve

Simple idea but works very well. Stops the breeze comming through the ducting even on the windy days we've had

Mice simple device, installed and doing the job, star lost due to slower delivery time than promised...

Excellent quality fast delivery

Works great opens with extractor and closes when extractor is off and stops draft from coming in from outside

Utter rubbish. The flap kept falling off every time I tried to attach the hose so ended up leaving it off which kind of defeats the purpose.

The title says it all.

Simple and effective.

Does the job

We had problems with the fan in our laser getting covered with a layer of black shiny creosote. Had to flake off with screwdriver. After thinking about it we thought maybe the damp air was turning the dust from basswood into a coating. IT WAS! Get this for venting a laser, keeps moisture out and cold air from coming in through your vent.

A little costly, but the only one of its type i could find

Solid product.

Noisy and useless, when high winds come from the opposite side, the shutter opens anyway and it closes with a bang.

Bloquea el aire, todo lo que se le pide a este producto.