DC12/24V battery tester can accurately check the power status of car, truck and motorcycle battery. Charging alternator check. Operating range: 9.9V - 16.2V / 20V - 32.1V DC. Heavy duty insulated clamp with 230mm 22AWG wire for safe and easy use. 7 LED indicators clearly show the status of the alternator battery. Nickel plated steel clips - easy inspection and access to the battery mounts. Multiple functions: alternator health check, battery health check, check before charging. The alternator check shows the status of your alternator based on the measured voltage. The external charging check shows that the battery is charged when an external power source is used. When using a DC lead-acid battery or a vehicle battery, battery problems can be quickly identified with this tester.