Digitally tests the connectivity and power voltage coming out from various vital PC power connectors - Tests ATX power supply connector from PSU regular HDD/DVD power connector and SATA power connectors - Displays results via the on-unit LED panel (labelled in English) - Full support list: ATX 24P/20P/8P/6P/Floppy - This is the Chinese version. English version is available - click here . - Note : this unit does not come with any user's guide. See the last picture for a scanned user's guide for this device (but in Chinese). In the meantime the device is very straightforward and easy to use.