Mild steel barrel nipple, welding nipple, close nipple, hose nipple American standard: ANSI/ASTM A733 Steel pipe Standard : ANSI/ASTM A 120 (SCH 40) Thread Standard: ANSI B1.20.1 British standard: BS1387 Steel pipe Standard : BS1387 Thread: BS21 DIN standard: DIN 2982 Steel pipe Standard : DIN 2440 Threads: DIN 2999