It provides power to HD-31C HDMI Compact Switcher and MHDCP-EQH HDMI EQ AV Extender if it is not getting enough power from the HDMI port. NOTE: Must be used with HD-31C REV1, REV2 & REV3 or MHDCP-EQH. (Input Voltage: 100-240v 50-60Hz / Output Voltage: 5vDC 2Amp; Connectors: AC 2-Prong to DC; Color: Black; Length: 4ft)