I had one many years ago and it had a set of wheels that would attache to it so you could pull it to the tree and then pack a deer out. The wheels were large, spoked wheels with bicycle tires.
I have a friend who has one that his buddy made him out of electrical unistrut and emt conduit that is welded together. They welded the bolts and used wing nuts. Heavy duty and it's probably stronger than an actual original one. He said they made about 5 of them after one guy bought one. One of the guys wives worked at an Upolstery shop and made them all a heavy duty double stitched canvas sling seat.