The Complete Repair Kit is compatible with the 3/4 in-1 in Model 975XL and 975XL2 Reduced Pressure Principle Backflow Preventer. Repair Kit components include two Check Seat O-Rings, two Check Seats, two Retaining Bolts, two Seal Ring Retainers, two Seal Rings, two Poppets, one #1 Check Spring, two Cover O-Rings, one #2 Check Spring, one Relief Valve Stem O-Ring, one Relief Valve Seat O-Ring, one Relief Valve Seat, one Spring, one Retaining Bolt, one Seal Ring Retainer, one Seal Ring, one Lower Plunger, one Diaphragm, and one Upper Plunger. The accessories within the kit allow you to speed up repairs, while lowering maintenance costs and extending the product life. The Zurn® Wilkins portfolio offers long-lasting protection from back siphonage and backpressure of contaminated water into the potable water supply.