Easy to use battery tester to check the status of your car battery. Save time and money checking the battery life yourself. Just plug in to the 12V cigarette lighter in your car, the LED indicators will show you the status of your battery and alternator. 3 LED indicators to show the battery condition: weak, normal or strong. 3 LED indicators to check the status of the alternator voltage: low, normal or high. Compact size, a handly item for your glove box so you know right away if the problem you have is related to the battery or alternator. You can make a decision yourself based on this tool whether the battery or alternator needs to be replaced.