Components in these Marinco charging systems are completely sealed in waterproof thermal epoxy to prevent damage and corrosion. Three-stage charging cycles for fast recovery, overload protection with automatic resets, LEDs to indicate charging status and “Smart” technology to prevent battery damage even when the charger is left on. All models can be left on for maintenance during storage. Use with any battery type, even gel cells and 12-, 24- or 36-volt systems. A waterproof housing protects internal electronic components.