TimerPlus is the best tweak to enhance the timer function on IOS.It integrates perfectly in the native Clock application.With TimerPlus,you can make the timer better:
1. Before you can only set a ringtone when the timer ends. But Now more than 20 new actions you can set. Like power off , reboot , turn off wifi, turn on 3G...
2. Get an alert 30 seconds before the timer ends.
3. Get an alert when the timer fires.
4. You don't need go back to the Clock application to check a timer that is running. You can see it just in the Notification Center. (TimerPlusWidget)
See larger Screenshots below..