1,2,3 SAIDAS 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~20.08mmAmerican Standards CGA-320:60` 21.08mm*19.11mm~19.41mmRussian Standards G3/4"-14TPI(lvory) 55`26.441mm*24.117mmChina Standards G1/2"-14TPI(lvory) 55`20.955mm*18.63mm CO2 regulators for dispensing beer