The concept of how much time is left, is difficult to grasp, especially for our special education students. These unique timers provide a clear visual display of the time remaining. Set to any time between 1-60 minutes, time is up when the red shield is no longer visible. Timers run silently but now have the option of a single auditory cue to indicate the end of that session. You can set the auditory response mode or not, depending on need. Easy to read dials; battery operated (1 AA-not included). The small personal timers are great for keeping individual students motivated, so you may need more than one. Time Timer Plus now has a protective lens, built in handle and volume control.