The Topeak SmartGauge D2 is a must for every toolbox. It is an all purpose pressure gauge and works on bike tires, shocks, motorcycles and cars. Tire pressure is often overlooked, but is critically important for performance riding and floor pumps gauges can vary in accuracy. Low tire pressure can lead to pinch flats and slower time trials. Running too much pressure can lead to unsafe, poor cornering performance especially in criterium racing. Also, lighter riders should use less pressure than heavier riders for safe performance corning. The Topeak gauge will allow you to maintain exact tire pressure to ride your best!