190 mm x 190 mm Plastic ducting air inlet / air outlet with gravity shutters - 6 inches / 150 mm round male spigot on the back of the grille for indoor or outdoor use. Designed to terminate your extract duct to an external wall. 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. Gravity operated flaps that close when not in use. 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.