Timers allow you to keep your lite lit for a specified period of time, when you turn it on.  It will show a counter on the lite to let you know how many seconds you have before it will automatically turn off.

In its default configuration the lite will stay on forever, or until you turn it off.   There are two controls that let you change to configure this.  

One is the toggle switch that tells the lite to count down until it times out.  It is labelled: “Switch starts timer“

The other is the Time Picker that is labelled: “How Many Seconds“, which lets you set the timeout value.  You can specify the time that it will stay on, in the preference pane, to any time between 0 and 999 seconds.  If you do not set this it will default to 15 seconds.

This is great if you are using your lite, you want to minimize battery usage and you just need a little extra time.  If you use this option in combination with the AutoOff, as soon as the timer runs out, it will shut your lite off and quit the application.