Insten 20/24-pin Power Supply Tester for ATX/SATA/HDD, Black Prevent electrical disasters by testing your power supply regularly to identify problems before they damage your computer. Monitors voltage output. Green LED display lights-up when your devices is running smoothly. Easy to use, plug-in design. Sturdy plastic. Tests PC 20/24-pin, PSU, ATX, SATA, HDD.