Available on Quadratec but I went direct to the manufacturer,
American Outlaw Jeep Parts. Prefer dealing direct and it was a few dollars cheaper.
I looked at a bunch of standard door stoppers on the web. Most looked like they would collapse with the weight of the tailgate, spare, tire carrier and loaded cargo basket. I've been using this for a few months, mostly while camping, and it is performing flawlessly. If I were to doit again, I think I would mount it to the bottom hinge.