Zurn Wilkins 34-350XL 3/4" Lead-Free Double Check Valve Assembly ASSE Listed 1015, IAPMO Listed, CSA Certified B64.5 Main valve body: Cast Bronze, ASTM B 584 (3/4-1") Housing: Reinforced Nylon, Fasteners: Stainless Steel, 300 Series Elastomers: Silicone (FDA Approved), Buna Nitrile (FDA Approved) Internals: Delrin, NSF Listed, Springs: Stainless steel, 300 series