Ventilation Pipe Round Check Valve is a backdraft prevention device for round ventilation ducts. It functions as a draft blocker and hose proof valve for exhaust fans, helping to stop reverse airflow and reduce drafts when the fan is not running. Key benefits Prevents backflow: stops reverse air movement in ducts, keeping outdoor air, odors, and pests from entering the living space. Improves energy efficiency: reduces heat loss or cold drafts without affecting normal fan performance. Simple, versatile fit: designed for round ventilation pipes and exhaust hoses, compatible with a range of standard duct sizes. Easy installation: straightforward inline installation that works with common ductwork and exhaust hose connections. Reliable oneway operation: maintains unidirectional airflow to support consistent exhaust performance. Key attributes Sizes: 80 mm, 100 mm, 110 mm, 150 mm, 200 mm. Functionality: round check valve that acts as a draft blocker and exhaust hose proof valve. Compatibility: suitable for standard round ventilation pipes and exhaust hoses. Material: material information not specified. Performance: designed to provide effective backdraft protection while allowing normal airflow when the exhaust system is operating. What makes it useful A compact, inline solution to prevent unwanted air ingress and odors when ventilation equipment is off. A practical upgrade for improving insulation and comfort in areas with vented spaces. Applications and use cases Residential bathroom and kitchen exhaust systems: install in the duct to prevent cold drafts and odors from backflow when the fan is not running. Exhaust hose connections for range hoods, bathroom fans, or laundry vents: use to stop backflow and protect indoor air quality when the fan is off. Attic, basement, or other vent lines: place in round ducts to block winddriven reverse airflow and improve overall insulation and comfort. Installation notes Designed for inline use with round ventilation pipes and exhaust hoses. Select the appropriate size (80, 100, 110, 150, or 200 mm) for your duct diameter and install in the airflow path to ensure unidirectional flow.