When your auto battery is low, there is no one around for a jump and you don't have time/electric to wait for a slow charge, this booster is the ticket. Starts a low powered battery instantly. Has saved me several times when I had a car battery getting too old or when I left interior devices/lights on. Easy 2 connector hook-up, turn it on, start your auto, then turn the charger off and disconnect. It's that easy! I keep one in every vehicle I own and have given them to several loved ones. Makes a great Christmas/birthday gift!