The iGuard works with a combination motion sensor and a count down timer. The count down timer starts to count only AFTER the motion sensor can’t see you. If you return while the timer is counting down it will automatically reset to its maximum time. If it times out and shuts off the stove while you were out it will automatically turn the stove back on when it sees that you have returned. Plus it has a lot of other great features listed on the features page.