Use the Traveller 5 - 150 PSI Pro Tire Pressure Gauge to keep an eye on your tires. You can improve your gas mileage by around 3% by keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by 0.4% for every 1 PSI drop in pressure of all 4 tires. Properly inflated tires are safer and last longer. This digital tire pressure gauge offers easy readouts in PSI, kPa and bar and features simple push-button operation. It's also equipped with an auto-off feature to help conserve power between uses.