A simple and easy to use battery and alternator tester, suitable for use on both 12V and 24V DC systems. The LED display gives a quick and decisive indication of power out, and features two alternator readings: Alternator over-charging, Alternator OK (13.5V), and three battery readings: Good (≥ 75%), Fair (≥ 25%), Poor (<25%), to quickly identify if either are at fault. It is also fitted with a large magnetic strip, on the rear of the tester, to allow for it to be attached to the inside of the engine bay or bonnet, for ease of use.