The 10" Watts 994 Series Reduced Pressure Zone (RPZ) backflow preventer began production in 1998 and is still currently in production. The body is contructed of stainless steel and uses a single victaulic coupler cover. The 994 utilizes plastic cam checks and a self contained stainless steel relief valve. The relief valve may be removed from the body by unthreading it, but use caution when doing so, as to not "squeeze" or warp the relief valve body. Check assemblies bolt into the body. No special tools are required for servicing.