The NIBCO® Ring Check® valve is constructed of high quality lead-free* dezincification-resistant (DZR) performance bronze silicon alloy per ASTM specifications. The Ring Check® valve is uniquely designed with an in-line, spring assisted self-closing disc. The lift check valve prevents backflow by automatically closing when fluid reverses direction. The lead-free valve is recommended for applications that deliver water for human consumption, including commercial and residential construction.