The 2 1/2 - 10" Febco 826YD Series reduced pressure detector assemblies began production in 1989 and is still currently in production. Early models were painted epoxy ductile iron. In 1991, fusion epoxy coating replaced the painted epoxy coating. 2 1/2 - 3" checks do not have contained springs while the 4 - 10" check designs are self contained and require a spring compression tool to change springs. No special tools needed to replace rubbers. Checks are constructed of stainless steel. The relief valve utilizes an external sensing line hose. The bypass device is a 3/4" 825Y.