This Ever start 991W Miniature 6-12 Volt Battery Tester is a simple and convenient way to test your batteries to see if they have life remaining. You do not want your battery to run out unexpectedly or when it would be difficult to replace it. You can use this tester to check the battery before you start out on an adventure. It is easy to use and it is small and portable so you will always have it with you. You can keep it in your gear bag or anywhere else it might come in handy. It can test batteries that emit between 6 and 12 volts of power. The car battery tester can determine the amount of charge remaining in your battery. This lets you know if you should replace your battery and prevents you from being caught unprepared. The lead acid battery tester tests the acid remaining in the battery to alert you if your battery is running low. It is convenient and portable and you can keep one with you at all times.