Air compressors can do a lot of things, from driving power wrenches to spraying paint. Perhaps the most basic function of an air compressor, however, is to inflate things, especially tires. With the right attachments, you can reinflate any tire, whether it's on a bicycle or a big rig.
Before you can attach any inflation gear to your air compressor, you'll need a union fitting attached to the end of the compressor's air hose. These fittings accept the male plug from the inflation device and must be sized to fit the plug. Most inflation devices have a 1/4 NPT plug, so that's the size of union fitting you'll need.
An air inflator with integrated gauge is a device that plugs into the union fitting. It features one or two trigger-style switches and a long rubber hose that ends with a coupler that clamps onto the tire's air nipple. When you pull the trigger, the gauge shows you how much air pressure is in the tire as you inflate it. This helps ensure that the tire is fully inflated but not overinflated.
One optional part you might want to add is a quick-connect air coupler. These use ball-bearings to grab onto the male plug of the inflator, so you can just push the plug into the coupler, rather than screwing it tight as you must with the union fitting. It can save you a little time if you're switching back and forth between several compressed air attachments.
