There are a lot of different CO2 charger devices out there that use small disposable CO2 cartridges, but this one actually has an adjustable pressure knob with a small gauge. it accepts either 12 or 16 gram threaded CO2 cartridges. These have improved pressure gauges that have a range of 0-60 PSI for better readability.
The low pressure side of the unit threads on to a Male Flare fitting such as that found on the flare keg QD, available as an accessory if you don't already have one. It takes between 1 and 2 cartridges to dispense a full keg of pre-carbonated beer.