ANSI ASME BS CNS DIN EN GB GOST SAE ISO JIS KS NF UNI SN YJT

[M] Metric [NPT] American National Standard Taper Pipe Thread [ZM] [Mc] [Mp] Metic pressue-tight joints threads [R] [Rc] [Rp] [R1] 55°Pipe Threads where Pressure-Tight Joints are made on the threads