Two stage designe, compatible with both Schrader and Presta valves,2 in 1 function * With switches of HI-P and HI-V modes for different types of bikes, such as mountain bike and road bike * HI-P mode: high pressure mode, easier pumping for tyres of high pressure * HI-V mode: high volume mode as more air per stroke, for tyres of low pressure * The pressure gauge can help you monitor the tire pressure directly