The Stanley 300 Amp Jump Starter is designed to offer maximum performance and jumpstarting the vehicle in a quicker way. Featuring visual and audible reverse polarity alarms to warn against improper connections to battery terminals. It has a built-in AC charger that recharges the unit with most standard household extension cords and a keyless on/off safety switch for greater user protection. This starter consists of ultra bright area light for increased visibility in dark areas and heavy duty cables as well as clamps that store easily on unit.