100mm / 4 inch External Stainless Steel Vent with Back Draft Shutter Featuring an integrated non-return backdraft damper and supplied with screws and cowl-to-wall rubber gasket, this stylish steel wall extractor hood vent outlet has an unobtrusive profile. A cushioned low noise flap prevents unwanted sounds from being heard from within the property. This also features a gravity flap to prevent small mammals and birds from accessing the ducting attached to it. The gravity flap is stylishly covered by the square shape cowl and in doing so, offers more of an aesthetic appearance than most traditional plastic grilles. Stainless steel cowls offer greater weatherproofing, and are not affected by ultra violet rays like some plastics can be. The grille can be cleaned using any stainless steel cleaner. Ideal for all tumble dryer vent pipes / hoses, bathroom vents & extractors, air conditioning units, kitchen fans & vents, home wall vents, heat transfer & ventilation systems, gas & electric dryers, cooker hood extractors, as well as a wide variety of industrial uses.