Battery Tender 021-0144 Plus 6V Battery Charger Temperature compensated to ensure optimum charge voltage according to ambient temperature. Automatically switches from full charge to float charging mode Battery Tender at 1.25 amps will charge as fast or faster than any 3 amp charger available. Reverse Polarity Protection to ensure user safety. Red and Green Lights Alternately Flash in this condition. Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode)