From the Manufacturer
The XPOWER JUMPCHARGER 40 is a powerful tool that recharges batteries and jumpstarts 8-cylinder engines. Compact and lightweight, this versatile Jumpcharger uses our Rapid Charge™ three-stage high frequency charging process that recharges your battery three times faster than conventional chargers. 40 amp maximum DC output current has selectable charge rate to fit all battery sizes (2/20/40A), built in storage, and easy to read LED display. JUMPCHARGER 40 also has a fault diagnosing tool for quick battery troubleshooting and a battery reconditioning function that reactivates flooded lead-acid batteries.