shut off valves: 1,copper and stainless steel materials, 2,OEM/ODM service; 3,at most 3 gases available. Description:1,Material: copper and zinc-plated steel and welded by silver;2,Full-port and ball-type (double seal) valve with a cast Stainless steel body and chrome- plated brass ball;3,The seal is Teflon and can endure pressure of 600 psi (Vacuum service to 29Hg);4,The knob Coating vinyl ...