This rectangular to round duct connector allows easy installation into existing systems Perfect for enhancing ventilation in bathrooms, toilets, and utility room, maintaining perfectly air circulation The Flat Ducting Adaptors ensures a smooth airflows conversion from 115mmx50mm rectangular to 4inch round ducts Make from, this Adaptors is designs to last in harsh conditions like kitchens and bathrooms This Adaptors works with extractors fan, tumbles dryer Vents hoses, and other Vents systems, ensuring efficient ventilation