Mini DisplayPort (mDP) to HDMI pigtail (2-4in cord) adapter. A male mDP connector provides a full resolution, digital female HDMI connector. Gold-plated contacts for worry-free operation. Matched-length, twisted pair wiring meets or exceeds HDMI spec for all modes of use.
This is an Active adapter which means that it has electronics in it to resolve any compatibility issues. Typically this is called “Eyefinity” and allows multiple HDMI monitors to work at the same time.
A pigtail adapter is typically used to convert the video signal to a format needed by the monitor. An HDMI to monitor cable is required to complete the connection to the monitor or other video equipment.