Pack of 5 handy-sized timers can time up or down to 99 minutes and 59 seconds. A beeping alarm is sounded when the time has been reached. Having dual power functionality (solar or battery operated) means they are always charged and ready to go. The push buttons have been designed for ease of use. The timers can be used in numerous experiments, for circle time, games timing of tests and a hundred and one other uses. Color-coded for easy identification. Includes built-in mounting slot and stand for hands-free use. Size: 2.55" x 2.55" x .50". Display measures 2" x 1". Recommended age 8+ years