The 1/4" Watts Series 009 Reduced Pressure Zone Assemblies are Watts "contractor grade" RPZ device. They began production in 1992 and still are being manufactured. 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. No special tools are required for servicing 009 Series devices.