I ordered the 50mm with the standard ball. I wish I would have gotten the 55mm because the 50mm is a little tight around my package. I'm an average-sized guy, and it's a big tight such that the skin doesn't move back and forth much so have to be lubed up for stroking. The ball is exquisite. I was skeptical when I was thinking of ordering, but am glad I did. Just wish I'd gotten the larger ring. All in all, though, I really enjoy it a lot!! Highly recommend it, and be sure if you're on the fence with the sizing of the ring, go with the next size up!