The one at work was a ‘2nd chance’ Kensington Orbit which was missing it’s top support, making it a tad unstable. I asked if that was by design, company gave a full refund and let me keep it. It’s safe at work, coleagues have no clue how to use it and it wobbles when in use. (When you don’t put a few post-it’s where the top support should have been)
I have 2 orbits with scroll ring at home, and a few marble mouses as spare. (But that scroll ring is adictive)