Great for elderly people living on their own. We test it every couple of months and it works every time. Mum has only accidently set it off once in two years and it is easy to cancel and she just rang to say she was fine.
Excellent product, easy for my mum to use and no on going costs.
Would be nicer if slighlty longer range as my mum has a very big backyard and it won't reach to the end of the yard.