I can only offer guesses, as I don't have the Ultimarc trackball. I do have a Betson, which is the base of of GGG's offerings. If you take the 2 1/4" option on the link you provide, the ball should fit perfectly. I have the same lighting kit on my 3" trackball - the LED module is meant to mount over a hole at the bottom of the Betson case. Not knowing anything about the Ultimarc, I can only advise that you might need to get creative on mounting the LED part. If you look at the first pic in the link you sent, you can see that it's a square board with screws and spacers. Take a look at the bottom of your Ultimarc and see if you can find a way to mount it. You may need to create a hole (just big enough for the LED's to show thru). The screws work their way into the plastic well - I don't recall if a small pre-drilled hole is required, but the instructions that come with the kit should cover that. Sorry I can't help more.