120 PSI Air Source Kits come with a low amp-draw, 25% duty cycle, 275C VIAIR compressor mounted on a 150 PSI-rated 1.5 gallon air tank with 5 ports. All Air Source kits come with a pre-wired pressure switch (P/N 20003 / 90-120 PSI). The 120 PSI Air Source Kit comes complete with a 1/4” NPT brass drain cock, 1/4” NPT ASME coded and certified safety valve, 1/2” NPT port compression fitting for 3/8” air line pre-installed. To use, simply connect the pressure switch to fused power, make a solid ground and connect an air line to the compression fitting. The use of a 40-amp relay and an appropriately-rated fuse is strongly recommended to preserve the life of the pressure switch.