A truly diagnostic 0.8 amp battery optimizer for 12V lead-acid batteries (sealed maintenance-free, gel, or filler caps). Like OptiMate® models, the microprocessor-controlled OptiMate® 4 can save neglected batteries and is even more effective with its new dual-stage Recovery and Turbo Recovery desulfating action. Sealed waterproof enclosure is ideal for snowmobiles and watercraft and also has special cables and bushings for ultra-cold temperatures down to -.40° F. New shape includes wall mounts, and now shows current display, hourly testing with easy to indentify results, plus 24/7 maintenance. Recommended for all 12V lead-acid batteries up to 75Ah.