UPGRADED CONSTRUCTION: Crafted from premium brass in one piece, the vacuum breaker check valve body offers enhanced durability. Opting for a one-piece spool over a spring and ball design allows for improved sealing and quieter operation, while maintaining a high sensitivity to water pressure. FUNCTION: This RV black tank anti-siphon valve is compatible with the b&b Model 571 Check valve. It is part of the black tank flushing system and is installed between the freshwater inlet and the tank flusher. Its design aims to prevent backflow and back-siphonage, ensuring the cleanliness and health of your freshwater source Easy To Install: Our vacuum breaker check valve features 1/2 inch NPT male threads on both the inlet and outlet, allowing for easy installation. When replacing your old check valve, ensure the correct installation direction: clean water should flow in the direction indicated by the inchFLOW inch arrows on the valve body. Once confirmed, connect the check valve to the pipeline. Note that the installation position should be approximately 6 inches higher than the flusher, and vertical installation must be ensured. Before installation, it's essential to cut off the water source and empty any residual water in the pipeline Compatible Model: Compatible for Forest River / 21 Grey Wolf / 2014 Wilderness / Keystone Passport / 2018 Winnebago / 2011 Keystone Cougar TT / 2015 Tiffin Open Road / 2007 Montana / Fifth Wheel / 2019 Keystone Sprinter. WIDE APPLICATION: The 571-VAC-CHK-A RV tank flush one way check valve is a dependable replacement for or leaking check valves, providing efficient water flow. It is suitable for a range of RV models, campers, travel trailers, and motor homes Color: Gold Material: Brass Raw tape Random colors, Not accepting designation Package Contents: 1 x Brass RV Backflow