The Kair Gravity Grille is a plastic air inlet/outlet designed for ducting systems. It features gravity shutters that automatically close to prevent backflow of odors, noises, or drafts. With a 155mm x 155mm external dimension and a 100mm (4 inch) round male rear spigot, it fits most comparable pipes and hoses. This grille is easy to install with a push-fit design and is suitable for various applications including bathroom, kitchen, or hydroponics extractor fans, as well as whole house ventilation, air conditioning, and HVAC systems. Made in the UK, Kair products are known for their durability and compatibility within the extensive Kair range, offering a complete ventilation solution. It complies with Part F Building Regulations and has airflow performance independently tested by BSRIA or BRE.