100mm Circular Duct Connector With Damper - Plastic 100mm (4”) round ducting connector with integrated gravity flap backdraught shutter. Designed for use in ventilation ducting, extractor fan systems and HVAC applications. Prevents Backdraughts - Helps prevent cold air, odours, debris and insects entering through the ducting when the extractor fan is not in use. Supports efficient airflow control in ventilation systems. Simple Push-Fit Compatibility - Fits inside 100mm rigid round duct pipe or approximately 102mm flexible ducting hose. Can also be used to join multiple duct lengths to create a longer ventilation run. Durable Plastic Construction - Made from high-quality PVC plastic. Resistant to cracking, fading and heat exposure for long-term use in ventilation ducting installations. Multiple Applications - Suitable for bathroom and kitchen extractor fans, cooker hood ducting, tumble dryer vents, inline extract fans, hydroponics and HVAC ventilation systems., Manufacturer: FANTRONIX