Battery LifeTester is a compact, easy to use Mhos Meter for testing 12 Volt rechargeable batteries. Unlike ordinary testers which only measure static criteria, the LifeTester measures internal conductivity, which is the best indicator of a battery's health and life expectancy. The conductivity value, expressed in Mhos (the inverse of Ohms or resistance), is easily compared to benchmark readings from the included Mhos Chart. The chart then categorizes the battery condition as “Best, Good, Weak, or Bad”. Every battery type has a characteristic Mhos value when it is brand new and fully charged. The LifeTester is powered by the battery under test and automatically warns when the battery voltage is too low for testing.