They range from a 1 second timer - up to a year timer! Here are some great pre-set timers ready to use. It's pointless - but you asked for it! Try the Fullscreen button in classrooms and meetings :-) Use this 15 Minute Full Screen? :-) Remember! A cool little 15 Minute Timer! Simple to use, no settings, just click start for a countdown timer of 15 Minutes.