A simple tool for testing ATX12V (v 1.3 and v 2.0) power supplies without fussing with voltmeters and probes. Simply plug the power supply outputs into the 24-pin (or 20-pin) connector to verify voltage of each ATX12V rail. Green for normal yellow for insufficient and red for over voltage conditions. Plus a separate Power Good signal for validating whether power supply as a whole is working or not. Quickly and easily check to see if your power supply is good or not saves trouble-shooting time.