IDEAL FOR FREQUENTLY-CHARGED VEHICLES AND EQUIPMENT! THIS IS NOT A CHARGER, IT'S A BATTERY PREFORMANCE SYSTEM. IT'S DESIGNED TO HELP SINGLE 12-VOLT LEAD-ACID BATTERIES CHARGE FASTER AND PROVIDE MAXIMUM PERFORMANCE AND POWER BY PREVENTING LEAD-SULFATE BUILDUP ON THE PLATES. IT ALSO WORKS ON TWO OR THREE 12-VOLT BATTERIES CONNECTED IN PARALLEL. THIS UNIQUE SYSTEM DOESN'T NEED TO BE PLUGGED IN BECUASE IT IS POWERED BY THE BATTERY ITSELF. IT WORKS 24-HOURS A DAY WHEN ATTACHED TO THE BATTERY. IDEAL FOR CARS, BOATS, COMMERCIAL TRUCKS, EMERGENCY VEHICLES AND MUCH MORE. FIVE-YEAR LIMITED WARRANTY.