{"product_id":"100mm-gravity-shutter-black-4-inch-extractor-fan-vent","title":"100mm Gravity Shutter Black - 4 Inch Extractor Fan Vent","description":"\u003ch5\u003eDescription\u003c\/h5\u003e\n\u003cp\u003eThe Knightsbridge 100mm gravity shutter is a black polycarbonate vent cover with three internal louvres that open under airflow and close by gravity when the extractor fan stops. Designed for installation on both internal and external walls, the shutter accepts 100mm rigid or flexible round ducting from standard 4-inch extractor fans.\u003c\/p\u003e\n\u003cp\u003eWhen fitted to an external wall, the shutter prevents rain penetration and backdraught air from entering the ducting when the fan is off. The gravity-closed louvres also block vermin and windblown debris from accessing the duct run. In internal wall applications, the shutter acts as a one-way valve that allows extracted air to pass through to a plenum or adjacent space while preventing reverse flow when the fan is not running.\u003c\/p\u003e\n\u003cp\u003eThe 152mm square faceplate fixes directly to brickwork or masonry using screw fixings through the four corner mounting points. The 22mm recessed depth allows the shutter to sit partially into the wall opening, while the 38mm projection gives clearance for the louvre mechanism. The polycarbonate construction resists UV degradation in external installations and tolerates typical condensation in bathroom and kitchen ducting without corroding.\u003c\/p\u003e\n\u003ch5\u003eSpecification\u003c\/h5\u003e\n\u003ctable class=\"spec_table\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eHeight\u003c\/td\u003e\n\u003ctd\u003e152 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWidth\u003c\/td\u003e\n\u003ctd\u003e152 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProjection\u003c\/td\u003e\n\u003ctd\u003e38 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRecessed Depth\u003c\/td\u003e\n\u003ctd\u003e22 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCut-out Diameter\u003c\/td\u003e\n\u003ctd\u003e105 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConstruction\u003c\/td\u003e\n\u003ctd\u003ePolycarbonate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFinish\u003c\/td\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch5\u003eDownloads\u003c\/h5\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0729\/8993\/3835\/files\/products_1503952_datasheet.pdf\" target=\"_blank\"\u003eProduct Specification Sheet\u003c\/a\u003e\u003c\/p\u003e\n\u003ch5\u003eFrequently Asked\u003c\/h5\u003e\n\u003cp\u003e\u003cstrong\u003eWhat size wall opening is needed?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe cut-out diameter is 105mm to accept standard 100mm ducting with a slight tolerance. The 152mm square faceplate then covers the opening and fixes to the surrounding wall surface.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the shutter require power to operate?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. The louvres open passively under the airflow from the extractor fan and close by gravity when the fan stops. No electrical connection to the shutter itself is needed.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan it be used on an external wall exposed to weather?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. The polycarbonate construction resists UV degradation and the gravity louvres are designed to seal against rain penetration when closed. The shutter is specifically intended for external wall installation in typical UK weather conditions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is it cleaned?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eWipe the external louvres with a damp cloth to remove dust and debris. For internal ducting condensation buildup, disconnect the ducting from the rear and rinse the louvre mechanism with warm water, then allow to dry fully before reinstalling.\u003c\/p\u003e","brand":"Knightsbridge","offers":[{"title":"Default Title","offer_id":45293804060939,"sku":"EX007B","price":3.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/8993\/3835\/files\/107492_c1be8e91-5740-474e-baeb-6ef1c3cdd7e4.jpg?v=1714664441","url":"https:\/\/niori.co.uk\/products\/100mm-gravity-shutter-black-4-inch-extractor-fan-vent","provider":"Niori","version":"1.0","type":"link"}