Rachel per the Tumblr replies

Whipr portable rowing machine

this gonna be the most compact one out there (for actually a decent price)

ooh, thanks! I'd been looking on Amazon, and didn't feel like I was looking at the most, uh, safe stuff for a very similar price point. This one has some more steps to assemble/break down, but honesty it looks like that opens up a lot more storage options than the ones that fold into a tall, heavy pole shape

(of which many don't have wheels on one side, you just kinda gotta do the buff lift and waddle, which is how i move the exercise bike)