Power Probe IV w/Case & Acc - Red (PP401AS) [Car Diagnostic Test Tool Digital Volt Meter ACDC Current Resistance Circuit Tester Fuel Injector Tester] Supplies Power and Ground for Functional Component Testing Digital Volt and Ohmeter for circuit testing Large Color LCD Screen with Easy to Navigate User Menu AC-RMS, AC Peak to Peak, Frequency and Pulse Width for signal testing Fuel Injector tester for easy circuit diagnosis PCM/ECM Driver supplies safe voltage for testing computer driver circuits.