This LED Power Supply Tester gives you the tools to make sure that your power supply is fully operational and ready to work! It will tests 24-pin or 20-pin, floppy, HDD/CD-ROM, SATA, 4-pin (P4), 8-pin (Dual CPU) and 6-pin (PCI Express) connectors and is compliant with ATX, BTX and ITX power supplies! Use this Power Supply Tester to test your power supply if you don't have a motherboard to plug in to. But if you think that the power supply is bad and don't want to risk frying your motherboard, then this is the perfect device! Just plug it into the power supply's 24-pin ATX connector, and it will turn the power supply on. The LED lights will indicate the status of the voltage!