These fittings are specifically designed for is in potable, non-potable and hydronic systems; this includes commercial as well as residential. They are certified for underground applications and as manufactured joints without access panels. They are for use with: Copper K, L, M and annealed M; PEX (with tube stiffeners); CPVC. These lead-free dezincification-resistant (DZR) fittings and valves are made of high quality lead-free brass. Certified to 200 psi and 200°F. Fittings meet NSF/ANSI 14, 61 and 372 ad ASSE 1061. *Lead Free refers to the wetted surface of pipe, fittings and fixtures in potable water systems that have a weighted average lead content = 0.25% per the Safe Drinking Water Act (Sec. 1417) amended 1-4-2011 and other equivalent state regulations.