An HDMI extender usually consists of a single or couple of devices that are powered with a 5V DC from an HDMI source such as a Mac or an external power source. Although transmission via HDMI cable is limited, an extender can surpass this using fiber optic technology.
This device usually has a receiver and the sender that are connected through HDMI cables to the display and source. At the same time, this device can send signals to far away distances utilizing a receiver and transmitter. There are several HDMI extenders available today for the Mac.