The 1" Watts Series 009 Reduced Pressure Zone Assemblies are Watts "contractor grade" RPZ device. They were in production from 1989-1992. The original 1" 009 was replaced by the 009M2 in 1992. The 009 features a one cover design and is constructed of bronze and use check modules that slide into the body and are held in place with a retainer. The relief valve assembly slides down between the retainer and is directly under the cover. The check modules and relief valve assembly come apart for service. The original 009s parts do not interchange with the "M" models, so please be sure which model you have before ordering. No special tools are required for servicing 009 Series devices. Maintenance ManualSpecification Sheet