Prevents unwanted odors, noises, or drafts from reversing into your ducts. Features a gravity flap, eliminating the need for breakable springs. Ideal for preventing odors from flowing backward in ducts or when connecting two or more extractor fans to the same duct. Also useful for connecting multiple pipe lengths to create a longer duct. Simple to install and sturdy; just push-fit the duct and fittings together. For permanent installations, seal joints with silicone sealant or tape. Compatible with any female part of the Kair ducting range. Made from high-quality white Polystyrene/Polypropylene plastic material for durability. Temperature range: +60°C to -15°C. Complies with Part F Building Regulations.