After extensive testing, we've found the best tire pump on the market. Just set the desired pressure and inflate, the pump turns off when the tire is at the desired pressure. Pump only weighs 109g and 70mm x 40mm x 30mm which is smaller than any manual pump, easily fits in your pocket. Getting your tires to the right pressure has never been easier! Pressure gauge built in! Pressures set in PSI, BAR Presta and Schrader Max PSI 120 USB charging LED light for night use 1/3 size of a standard iPhone Real world testing: 1 minute inflation from 0 psi to 20 psi for an average mountain bike tire from flat. At very low pressures, the pump's gauge might be off by about 1 PSI. For example: Setting the gauge to 2 PSI will actually inflate to around 3 PSI. Setting it to 5 PSI will inflate to about 6 PSI. If you're inflating something that isn’t completely flat, first attach the pump and check the pressure reading on the gauge. Then press start to inflate. This ensures you're starting at the correct baseline pressure.