The HUDY Personal Racing Display is a compact all-in-one data center for professional RC car drivers, allowing you to record pertinent data for your set-up sheets. The display features large character and symbols for quick and easy readings. Aside from all of the data information, the built-in adjustable alarm clock can be used to notify you of your next heat or run. Powered by AAA 1.5V battery (not included). A �must have� device for serious racers.