The BEECO Friendly Double Check Backflow Preventer Valve is designed to stop the reverse of flow of a liquid into a potable water system. The proper installation of a backflow preventer must be done by a certified expert under local codes and guidelines to assure the protection of the drinking water system. The Valve shall be certified to ASSE 1015, CSA B64.5 and IAPMO listed. Certified lead free devices.