This 190 mm x 190 mm plastic air inlet/outlet features a 4-inch / 100 mm round male spigot for easy push-fit connection to ducting. Designed for both indoor and outdoor use, it terminates your extract duct to an external wall. The non-return gravity shutters automatically close when not in use, preventing unpleasant odours, noises, or draughts from flowing back. Its gravity-operated flaps require no springs, ensuring durability and reliability. This grille is ideal for various ventilation needs, including bathroom or kitchen extractor fans, hydroponics fans, in-line extract fans, whole-house ventilation, passive ventilation, air conditioning, HVAC, and heat recovery systems.