A GPS-based speedometer that can be used on mobile phones or tablets. It has a built-in head-up display (HUD) function and also displays the address information of the current location. The speed can be selected in kilo meters and miles, and the presentation of information can be changed both horizontally and newly. How to use When you touch the screen, an action bar appears. If there is no action, the Action bar will automatically disappear after 20 seconds. You can set the information on the screen to the desired format through the setting button on the action bar.