The Power Probe 4 Diagnostic electronic circuit and component tester supply battery power and ground. Featuring AC/DC Voltmeter, Ohmmeter, Frequency, Pulse width (Positive and Negative) and additional diagnostic modes: Fuel Injector Tester, PCM/ECM Driver Tester, and ECT Signal Tracer. Supply Power or Ground for Functional Component Testing Self-Resetting Thermal 8 Amp Circuit Breaker Multiple DC Volt readings on the same display Ohmmeter provide active feedback 12 ? 24 Volt Range Bad Ground Indicator Continuity Tester Component Tester AC-RMS, AC Peak to Peak, Frequency and Pulse Width indicators are available for signal testing Fuel Injector tester for easy circuit diagnosis PCM/ECM Driver supplies safe voltage for testing computer driver circuits PPECT Mode for signal detection of open circuits ( When used with the ECT2000/ECT3000 ) Active LED Lighting for illuminating workspace Power Cable Length of 23 Feet