The Shopsmith version is currently $129.99:
https://www.shopsmith.com/ownersite/catalog/keyless_chuck.htm
The ones on eBay look very similar, possibly from the same source. One of them claims a 3/4" grip which may be of value to some. I agree with
RFGuy, the Shopsmith version on sale does seem like a good deal since it comes with a warranty.
Interesting that this is so heavy, it weighs in at 3-1/2 lbs. So it should be sturdy enough to hold drum sanders and carbide burrs and other such utility tools on top of drill bits. It is long though, 6" end to end. Comments indicate that it's mounted in a 5/8" arbor of some kind that must account for that additional length and perhaps a good deal of the weight.
So not something I have a serious need for but I can see the appeal. If you have no chuck this would be as good of start as a conventional keyed chuck.