This is an amazing deal if you are looking to add a Kinect sensor to you Xbox One set up. At the time of posting this deal 25 units are available.
Important:
It's somewhat unclear whether this is new or second-hand stock. I believe it is second hand stock, however perhaps if someone has experience with this retailer they can share their experience in the comments section. In the meantime, buyer beware.
It's CEX - Computer EXchange - so it's almost certainly someone selling them the sensor that comes with an XBone package to reclaim some of the money.