GoldenEagle® Series LF719 Double Check Valve Backflow Assemblies and LF919 Reduced Pressure Zone Backflow Assemblies are designed to protect potable water supplies in accordance with national plumbing codes and water authority requirements. Both have been developed to provide both trouble-free operation and ease of service in all types of water conditions. Series LF719 is to be used in cross-connections identified as non-health hazard applications, while the Series LF919 is meant for those cross-connections in health hazard applications.