This useful tool features a normally-closed air chuck that can be opened by pressing the lever on the inflation gun. Because this air chuck is normally closed, the Tire Inflation Gun is a perfect compliment to onboard air systems. To inflate a tire, simply connect to an air line from your air tank and connect the tire chuck to a tire or other inflatable item valve stem and squeeze the tire gun trigger. This will open the air chuck and release air from the tank into the tire. To check pressure, release the trigger and note the pressure reading on the 0-200 PSI gauge. Carrying case included.