The digital timer is a countdown timer and a stopwatch in one. Great for math exercises, science experiments, timed tests, games,classroom management, and more. The timers sticks to whiteboards or any magnetically-receptive surface and include a retractable stand for desktop use. Counts up and down. Max duration is 99m 59s. Measures 3-5/8" L x 2" W x 3/4" H Requires 1 AAA battery (not included)