I have two GPS Tracker-one in each car. I feel so comfortable knowing that when my nanny is out with my kids, in either car, I can see where she is at any given moment. I don't allow my nanny to speak on her cell phone while she's driving my children around, so this is the best and safest way for me to check her whereabouts without calling her. While I trust my nanny, this feels like an second layer of security. I installed the device in the cars and I never have to think about charging it. It's as easy as plug and go. The monthly service charges are very reasonable for my peace of mind.Great device!!!!!