This 2" second check rubber parts replacement kit for series 009M2 is used for repairing the parts to the relief valve to prevent the reverse flow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure. This kit consists of a second check assembly O-ring, disc holder assembly, cover O-ring and sensing passage O-ring. Made for easy installation and use, it will help ensure the best service life possible.