I don't know about that. The t-bag I have (with wheels and retractable handle) has a piece that slides down over the backrest and straps to secure to the rack. Takes 30 secs. to mount and dismount. Mine carries a lot. I have had twenty bags over the years and I like this one best.
I use to shop on eBay a lot, but have seriously curtailed that; there's so much counterfeit garbage on there and eBay doesn't care as long as they're collecting seller fee's. Shady IMO
alright, got it in the mail yesterday and was able to put it on bike today. 1st impression is that it's way heavier duty than my last cheap leather luggage and I already like the fact that it has plastic insert to keep its shape! It's not as big as I was thinking it was though. I will probably have to add a topper bag to it for our 8 day trip. Zippers all worked well and there are plenty of d rings to strap down with. The velcro attachment that goes around the passenger backrest is just long enough but isn't able to fit very well because of the shape of the backrest. Overall, I'm happy with it and I'm sure it'll be fine for what I need it for! It came with a carrying strap, 2 tie-down straps, and a heavy duty rain cover.