Below is a list of 12 Volt Air Compressor manufacturers from Annapolis Junction, Maryland. A 12 volt air compressor is a machine that requires 12 volts of power to reduce the volume of air in a tank in order to increase the pressure. The pressurized air can then be used for a wide variety of applications; some cordless models of 12 volt air compressors can generate 220 pounds per square inch (PSI) while others reach 320 PSI.