experience with it yet. But, I had my girlfriend stand about a 1/4 mile away and she said it vibrated when I opened my door (the door on the car on the pager opened) and when I started my car the wheels on the car on the pager started rolling. I also tried the same thing when my girlfriend was inside my house and the Z was in the garage. It worked through the garage and inside the house. It's a lot smaller than a regular pager and seems to work very well. In my opinion, I'd say it was worth it.