Voltage:12 volt Outlet Fitting Size:1/8 NPT Max Air Pressure:150 psi Duty Cycle:15% Amp Draw:18 Amps Dimensions L x W x H:6.25 Inches X 3.25 Inches X 5.25 Inches. Firestone Air compressors are available in standard and heavy duty styles. All Firestone's Air Compressors are direct drive units that contain no oil or belts. This means your compressor can be mounted in any position without effecting the compressor's performance. Firestone air compressor and gage kits offer the broadest variety of air fill accessories available on the market today.