Cooling units can be used to create refrigerator compartments up to 10.6 Cu Ft. and freezer compartments up to 3.5 Cu Ft. All standard cooling units are DC powered and are provided with no refrigerant in the circuit optional units are available, upon request, with quick connect couplings and pre-charged with R134a refrigerant Depending on available power requirements, an AC/DC powered cooling unit is available (12-24/110-240V), using an AC/DC electronic module instead of the DC only module.