NPT Full Couplings Half couplings, Socket Couplings . Standard: ASME B16.9, MSS SP-43,MSS SP-75,ASME B16.11, GB/T14383, GB/T14626 ,DIN,JIS and so on. Size: 1/2"-24" seamless 12"-48" welded Materials: ASTM A234WPB, A105, A403,A182,A312, 304/304L/316/316L ,SS400,RST37-2 and so on.