Yes. I have a few. I think I have a couple different brands, but they're the same concept and look very similar.
There's a thread on here somewhere from spring/summer with pics and descriptions of a few of these.
I ended up taking the seat off and making a sturdier platform on one of mine. I think someone else here did too , (probably several others) and eventually ended up using the new"seat" as platform mounted on shortened Muddy sticks.
They work really well