Battery Tender Battery Tester Takes only seconds to measure battery condition No external power required Easy to use - requires only 2 digit type code Measures 2.3 to 30 AMP hour capacity and 10 to 500 CCA Built in voltmeter - 8 to 19 volts Works on discharged batteries Reverse polarity protected - No Sparks, No Heat Durable portable design for shop or field use Weighs only 1 lb. 2 year limited manufacturer's warranty Always use a battery charger with a nominal output voltage that matches the nominal battery voltage. (i.e. 12 volt charger for 12 volt batteries)