This Kair Gravity Grille is a 125mm / 5-inch air exhaust outlet featuring a round spigot with non-return shutter flaps. These flaps automatically close when not in use, preventing unpleasant odors, noises, or draughts from flowing back into your property. The 5-inch / 125mm round male spigot on the back fits inside most comparable size pipes and hoses, such as Kair 125mm Round Female Duct Pipe or 127mm flexible hose. Installation is simple with a push-fit design, and sealing can be done with methods like mastic sealant, poly cement, or tape. It's ideal for various applications including bathrooms, toilets, kitchens, hydroponics, and cooker hoods. Made in the UK, Kair products are compatible with a wide range of fittings and outlets for a complete ventilation solution. This grille can be part of a longer ductwork run for whole house ventilation, passive stack ventilation, positive input ventilation, air conditioning, HVAC, and Heat Recovery systems. The 155mm x 155mm external dimensions and 5-inch / 125mm rear spigot are suitable for indoor or outdoor use. The gravity flaps require no springs, ensuring durability. It complies with Part F Building Regulations and has independently tested airflow performance.