All standard keg couplers produced for the U.S. market have the U.S. beer industry standard 7/8"-14 threads on both the gas-in and beer-out ports. This universality of threads allows easy switching of keg couplers without the need to cut hoses or even the removal of clamps.

To change from one coupler to another, first turn off the CO2 gas using the shut-off valve on your regulator. Then, on the coupler being removed, simply loosen the hex (or wing) nut fittings on both the gas and beer hose assembly and remove the hoses from the coupler. Then simply re-connect the hoses to the coupler you are wishing to use, and re-tighten the hex (or wing) nut fittings. Lastly, turn on the CO2 gas using the shut-off valve on your regulator.

If you have a few couplers you change between often you may want to consider a set of quick disconnects.

 

The exception to this rule is the Twin probe coupler, commonly used by microbreweries and craft breweries. Those couplers do not have a threaded gas port. Also couplers used for dispensing home brew beers lack the same, as well as a non-threaded beer port that allows for a hex (or wing) nut type fitting.