Used to extend my Oculus Rift headset cable. Where people have issues extending the Rifts cable, this thing saves the day. Provides a repeated and powered signal of your HDMI and USB cable coming from the Rift, providing another 6-10 feet of lossless extension.
Does not come with a AC adapter. I can provide that for another $20 if you need.
Or use it with your Vive of course. Or whatever else it's good for!