The Techno Tools Heavy Duty Battery Condition & Charging System Tester, No. B400, is designed to test 12V heavy duty auto, truck, commercial, and marine batteries and 12/24/36V starter and charging systems including 42V Mild Hybrid systems. The battery size is not required to be entered into the unit; simply choose between automotive or truck battery type batteries for testing. The B400 eliminates tester input errors and allows the testing of batteries of unknown size. It can also test both flooded lead acid and AGM batteries. The tester includes 4' heavy duty abrasion resistant cables for trucks with hard-to-reach battery compartments. The tester is made in the U.S.A.