After scoring a great deal on a shiny dual stage regulator in eBay, more often than not, you would usually have to convert the regulators nipple to CGA-320 fitting that's a standard in CO2 cylinders here in the U.S. Removing the installed fittings can be a challenge sometimes so we recommend the removal of the pressure guages first to prevent accidentally damaging them. We carry both brass and chrome plated CGA320 Nut and Nipple in 2 and 2.5 inches.
CGA-320 Nut and 2.5 inch Nipple for CO2 Regulator. Includes nylon washer. This part attaches to the regulators inlet and used to convert non-co2 regulator to co2 service.