The GB20 is a portable lithium-ion battery jump starter pack that delivers 400-amps (4,650 J3S) for jump starting a dead battery in seconds. It features a patented safety technology that provides spark-proof connections and reverse polarity protection making safe and easy for anyone to use. It’s a powerful battery booster that doubles as a portable power source for recharging USB devices, like a smartphone, tablet and more. Designed for a car, boat, motorcycle, RV and more with gas engines up to 4 liters.