Unlike the floaty Steam Box rumours this looks like the legit Steam VR unit.
It's not entirely clear yet but it is supposedly the official Valve Steam VR system (with the Valve logo and everything). The description says that HTC are developing the hardware and it will run alongside a base running "Steam VR." The current assumption is that the Steam VR base is your PC and the headset is just that.
It's supposedly a more interactive experience than other VR headsets (e.g. Oculus Rift, Project Morpheus, or Samsung Gear VR) in that it detects spatial physical movement in a space around 15x15ft. So theoretically you'd be able to move around the space rather than just the static "sit and look around."
There's still a lot of speculation. Until the dev kit is out this season we won't really know for sure.
Still, Valve being involve din its development is suggestive enough.