PDF Standards IEC 60169-10 Amd.2 Ed. 1.0 b:1996
Amendment 2 – Radio-frequency connectors. Part 10: R.F. coaxial connectors with inner diameter of outer conductor 3 mm (0.12 in) with snap-on coupling – Characteristic impedance 50 ohms (Type SMB)
Amendment by International Electrotechnical Commission, 03/20/1996