12V/8A 24V/4A Automotive Battery Charger/Maintainer, Power Your Device, Power Your Life. ENVIRONMENTAL CHARACTERISTICS: Operating Temperature Range: -20~45°C (-4~113°F) Storage Temperature Range: -30~75°C (-22~158°F) Operating Humidity Range: 90%RH Max AC Cable Length: 39.3 inches DC Cable Length: 21.3 inches NOTE: If it has been idle for along time, old or cannot be charged, select "REPAIR" mode to try to activate the battery. NOTE: IT CAN'T JUMP START CAR, JUST HAS BATTERY CHARGING FUNCTION. REMARK: for 4Ah-15Ah battery, we suggest use “REPAIR” mode, because the battery size is too small, use pulse charge is very good for small size battery. PACKAGE: 1 x Automotive Battery Charger 1 x User Manual