Vents 4 inch Black External Gravity Grille Air Vent Cover 100 mm Extractor Fan Back Draught Shutter Covers Ducting Tumble Dryer Bathroom Outside Wall Ventilation Hose Duct Grill

Airflow operated gravity shutter is a rain and weatherproof vent finished in black colour. The item is made from premium quality plastic. The overall external dimensions of the grille - 155 mm x 155 mm with 4" / 100mm dia duct connection size for outdoor use. The grille has three non-return gravity flap outlets. The shutter works by extract air opening the blades to allow air to pass. When the extractor fan or ventilation system is not in use, the grille shutter flaps close automatically. This is designed to protect your ventilation duct from unpleasant odours, noises and to prevent backdraught air or rain penetration, and entry of objects, or vermin when the ventilation unit is not in operation. Simple and secure installation. Just push-fit duct and fittings together. If required, seal using a method of your choice (Popular options include Mastic Sealant Poly Cement or Tape). This gravity grille cover can be used as a part of a long ductwork run for a variety of purposes: whole house ventilation, conditioning ducting, passive ventilation, positive input, HVAC, Heat Recovery Systems and to cover Bathroom, Kitchen air conditioning fans. The Gravity Outlet is manufactured in compliance with the Building Regulations: Approved Document F., Manufacturer: VENTS UK