1. Design and manufacture conform to BS5351 MSS SP-118; 2. Connection ends conform to: 1) Scoket welded ends conform to ANSI B16.11; JB/T1751 2) Screw ends conform to ANSI B1.20.1; JB/T7306 3) Butt-welded ends conform to ANSI B16.25; JB/T12224 4) Flanged ends conform to ANSI B16.5; JB793. Test and inspection conform to: API 598; GB/T13927; JB/T9092 4. Structure features: Bolted bonnet; three-piece; 5. Materials conform to ANSI/ASTM; 6. Main materials: A105; LF2; F5; F11; F22; 304(L);316(L); F347; F321; F51; Monel; 20Alloy.