If you mean a timer for uv etc, i use a digital one it plugs into the powerpoint.
Set it for an on and off time, then also set it to do it daily (this one can be set for certain days of the week) , u can connect it to more than one cage with a powerboard running from the timer.
That way you dont have to remember to turn on and off the lights

This one came from bunnings and was about $30 i think