This is a relief valve rubber kit for the Ames 4000SS & 5000SS reduced pressure zone assemblies. This kit includes all internal rubber parts inside of the relief valve. The relief valve unthreads from the device for ease of repair but use caution not to squeeze the body as it warps easily. Genuine Ames repair part. No special tools are required for servicing but a handy cam check tool is available to assist in removal and replacement of the cam check assemblies.