A tire gauge is a device to measure your tires' pressure. ARB's offers Red Small Dial Pressure Gauge (ARB506) and a Large Tire Pressure Gauge (ARB508). The Large Gauge is is specifically for lower tire pressure amounts in context to offroading and measures in 5 PSI increments and maxes out at 50 PSI. You can also check you tire pressure using a tire deflator or inflator.