Ames 200B Double Check Valve Assemblies began production in 2003 and are currently being manufactured. The devices are available from sizes 1/2 - 2" and are constructed of bronze. The 200B is the same as the Watts 719 and features two covers that thread into the body. The check assemblies are not self contained and the springs push pressure against the covers, caution should be taken when servicing. No special tools are required for service.