The 1/2" 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. In 2013, a lead free version became available, designated by the prefix "LF". No special tools are required for servicing 009 Series devices.