STEEL MERCHANT COUPLING & STEEL PIPE SOCKETS
USA STANDARD: ANSI/ASTM A120 
PIPE: ASTM A120(SCH40)ASTM A865
THREADS: ANSI B1.20.1
BRITISH STANDARD: BS1387
PIPE: BS 1387 BS EN10241
THREAD: BSEN 10241:2000
DIN STANDARD: DIN 2986
PIPE: DIN 2448
THREADS: DIN 2999