This easy to use Automotive Battery Tester can be used with all 12V lead acid batteries and alternators. The tester simply attaches to the battery or alternator and checks sufficient battery charge when starting and indicated charge level after a period on load, to provide users with a clear, precise indication of the condition of the battery and alternator. The CBAT1 features clear LED indicators which illuminate to indicate the test results. LED Indications: - Three LED indicators show whether battery condition is strong, normal or weak. - Two LED indicators show whether alternator output is too high or too low. - One LED indicator highlights a faulty battery