Ball and gate valvesare mainly applied in oil and gas industries. Standard reference for these valves is API 6A/ISO 10423. During manufacturing the high end range of these valves, that is special high pressure (5000 to 15.000 PSI), high quality demand (PSL2 or PSL3 forged construction), special materials (stainless 13% Cr, F6NM, duplex steels, nickel alloys) and extreme service conditions (low temperature, anti-wearing internals). Swing and piston check valves in accordance with API 6A are also available. A specific application related to oil and gas production are the valves installed on off-shore platforms and FPSO. Types and standards are similar if not identical to the valves used in the processing plants, with materials that have to consider marine environment (duplex steels instead of austenitic stainless steels) and sea water fluid.