The Ames 4000B is a reduced pressure assembly (RPA). It is available in 1/2″-2″ sizes and has been in production since 1997. The body is made of bronze. The 3/4″ 4000B has been modified and is notated by an “M3″ in the model number. A lead free version (LF4000B) was introduced in 2013. The 4000B is an Ames private label of the Watts 009.