CLA-VAL Co. 88419H 
Rubber Repair Kit for relief valve of backflow prevention devices 4" - 10" 
Part #88419H
Relief Valve Rubber Repair Kit 
For use on Models RP-1, RP-1 EX, RP4 -- sizes 4" - 10" 
95% of backflow preventer issues are easily corrected by replacing the perishable rubber parts inside the device.  
This is a rubber repair kit for the relief valve