SEV Fully welded ball valve are especially suitable for gas transmission and storage industries. The design of fully welded body avoids leakage between the body and cover under any working condition. The valve conform to API 607/API 6FA firesafe design, blow-out proof stem, anti-static design, DBB function, self-relief design and other features, it also can be selected according to customer requirement to provide double piston seat design, extension stem for underground installation.