It says to choose from 5.9" tall or 7.9" tall, but they offer only medium and large, both of which are 5.9" tall. Looks like a bait and switch.
Based on the manufacturers pictures, it looks like there’s should be a small height difference between the two, so yeah. The numbers are odd.
(Please note: I don’t work for Woot, I just volunteer to help out here on the forums.)
You might look up the definition of bait-and-switch before making that claim the next time. 
That part of the sentence was imported. I’ve removed so it will no longer offend you.
I purchased the large size & it just came on a Sunday too. It’s pretty big & the same height as a regular litter box. I wanted to switch it out because the plastic ones do get scuzzy & scratched (after several years & many cats). We currently have 4 cats & 1 of them sometimes likes to do their business on the wall or side of the box & we prefer the taller boxes mostly because of that. I’ll add a few pics below. It’s only a couple of inches shorter than a high sided box. I hope the cats take to it. If not it’ll go under a dehumidifier or a portable a/c in a carpeted room in case of leaks.
Hahaha thanks for the idea. Those things are sticky taped on. Would be better with velcro for cleaning purposes. We are good though.