Kair Black Gravity Grille 155mm External Dimension with 100mm 4 inch Round Rear Spigot and Not Return Shutters Ducting Air Vent

Black Plastic Ducting Air Inlet / Air Outlet with Gravity Shutters. 155mm x 155mm external dimension with 4 inch / 100mm round male rear spigot on the back of the grille for indoor or outdoor use. Non-return shutter flaps close automatically when not in use. Stops unpleasant odours, noises, or draughts flowing back through your duct. Gravity flap - no need for springs that could break. Easy to install, just push-fit duct and fittings together. Perfectly suited Bathroom or Kitchen extractor fan, Hydroponics fan, or In-Line Extract Fan. This grille can be used as a part of a long ductwork run for a variety of purposes including whole house ventilation, passive ventilation, positive input, air conditioning, HVAC, and Heat Recovery Systems. Suitable to use in compliance with Part F Building Regulations. Airflow performance independently tested by BSRIA or BRE. Free Air: 7200mm2. Static Pressure Drop in Pascals: 15 l/s = 10.94 Pa - 30 l/s = 18.59 Pa - 60 l/s = 24.21 Pa.