The Stanley SXAE00025GB Battery Charger and 4 Amp Maintainer is a great option for car, boat, or power sport batteries. Energy efficient and automatic, the unit features easy to connect clamp and ring terminal adapters. The microprocessor automatically adjusts the amperage rate, with multi-stage charging and float mode monitoring for optimum charging and maintaining to extend battery life. Includes scrolling digital instructions for ease of use and reverse hook-up protection which prevents the charger from operating if the clamps are reversed. Stanley meets the highest industry standards. Compatible with standard, AGM, and lithium batteries.