The Sealey SPI3S is a fully automatic microprocessor controlled battery charger & maintainer that benefits from patented speed charge technology, which actively monitors the charge acceptance & constantly modifies the charge output. This model charges the battery up to 3 times faster than conventional chargers without damaging the battery & its heavy-duty case, LED status lights, digital display screen, offering step by step instructions. This unit can charge conventional lead acid, calcium, AGM/GEL, leisure, stop/start batteries & is completed with reverse polarity protection, thermal runaway protection & automatic shut-off for added safety & battery reliability.