The Rubber Repair Kit is compatible with the 2-1/2” - 6” Model 975 Reduced Pressure Principle Backflow Preventer. Repair Kit components include one Diaphragm, one Spring Retainer O-Ring, one Stem Guide O-Ring, one Stem O-Ring, one Seal Ring, one Sensing Line O-Ring, one Large O-Ring, and one Small O-Ring. While the 2-1/2” - 10” large diameter 900 series valves are no longer in production, our 1/4” - 1-1/2” small diameter models are still available. For approved replacement options for our large diameter models, please see our 300 and 400 Backflow Preventer Models. Repair Kits are sold as accessories for quick and simple repair needs, providing long-lasting protection from backsiphonage and backpressure of contaminated water into the potable water supply.