The Complete Pressure Vessel Repair Kit is compatible with the 1/2” and 3/4” Model 375 and 375XL Reduced Pressure Principle Backflow Preventer. Repair Kit components include one #1 Check Seat O-Ring, one #1 Check Seat, two Poppet Screws, two Check Seal Retainers, two Check Seal Rings, two Poppets, one #1 Check Spring, one #1 Check Spring Retainer, one #2 Check Seat O-Ring, one #2 Check Seat, one #2 Check Spring, one #2 Check Spring Retainer, one Housing Inlet O-Ring, three Test Cocks, one Check Housing, one Housing Outlet O-Ring, one Relief Valve Cover O-Ring, one Relief Valve Seat O-Ring, one Relief Valve Seat, one Relief Valve Spring, one Relief Valve Seal Retaining Screw, one Relief Valve Seal Ring, one Relief Valve Lower Plunger, one Diaphragm, one Relief Valve Upper Plunger, one Relief Valve Stem O-Ring, one Relief Valve Cover, two Short Relief Valve Cover Screws, and four Long Relief Valve Cover Screws. 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 backsiphonage and backpressure of contaminated water into the potable water supply.