10 Underwriters Laboratory/Factory Mutual Flanged Swing Check ValveThe 10 Underwriters Laboratory Factory Mutual Flanged Swing Check Valve is a one way valve designed to prevent backflow in fire protection and water systems. It is UL Listed and FM Approved, ensuring compliance with fire safety standards. The swing type disc mechanism allows flow in one direction and automatically closes when flow stops, preventing reverse flow. Designed for use with or without a lever and weight. A spring kit is also available for