Forged carbon and alloy steel screwed and socket-welding fittings. Screw threads in accordance with API Std. 5B. Bore diameters of socket-welding fittings compatible with BS 3600 and BS 1600. Substantially agrees with ANSI B16.11, ASTM A 234 and ASTM A 403.Cross References:BS 131:Part 2BS 970:Part 4BS 1501-1506BS 1600BS 3600BS 3602BS 3603BS 3604BS 3605API Std 5BAPI Std 5LANSI B2.1