3-Piece Stainless steel ball valves with PTFE seals & seats Stainless steel 304 with excellent corrosion resistance for most applications. Working pressure: 1000PSI Medium: water, oil, gas/air, light alkali's and acids, biodiesel, fuels and alcohols. 316 2-piece ball valves with Stainless steel 316 body, cap and ball, all rest parts are stainless steel 304. so there won't be any rust formation from external air or water exposure over time.It should be noted that 2PC means that our ball valve consists of two parts, except the handle part, instead of two ball valves