ALLOSUN EM577 Black/Grey All-Sun Automotive Battery Tester The device is useful in vehicle's fault diagnosis and service: battery load test, cold Temp.Effects, battery load test analysis, charging voltage test, starter motor test (12V system only). Test batteries from 300-1000 CCA, operating range from 6-12 Volts. Compared with other pointer type battery tester, our bright digit LED display is great for bright- or low-light environment, which is easy to read the measurement result. This device takes the guesswork out of electrical diagnosis, making it easy to pinpoint charging system failures. Uses car battery for power, no extra internal batteries needed. Easy-to-carry and durable design