CO2 regulator 

 British Standards  G5/8"-14TPI(lvory) 55` 22.9mm*20.58mm~21.12mm

 Australian Standards 21.8mm-14TPI(lvory) 55`21.8mm*19.48mm~20.08mm

American Standards CGA-320:60` 21.08mm*19.11mm~19.41mm

Russian Standards  G3/4"-14TPI(lvory) 55`26.441mm*24.117mm

China Standards  G1/2"-14TPI(lvory) 55`20.955mm*18.63mm

CO2 regulators for dispensing beer