Designed to keep batteries at optimal charging capacity, the Duralast BC40DL Battery Charger and Battery Maintainer is both dependable and durable. This compact unit is compatible with all 12 Volt AGM/GEL/WET battery systems. The smart charger feature automatically selects the correct charge rate and then adjusts from rapid charge to maintainer to maximize battery life. You can also get a powerful 40 amp engine start to jump start most vehicles in 60 seconds or less. A patented alternator check allows you to perform a test to find potential alternator issues on the vehicle and its battery reconditioner technology can help to reverse damage. Includes heavy duty metal clamps.