The Last Spinner Cap (with concave)

I loved Zigians "The Last Spinner Cap", it fits perfectly and grabs the bearing really well - however, I prefer my caps to have a concave cup to hold your finger/thump in place. I took his 22mm wide "tall" cap, and added a small outside ridge and inner concave to it and it's now my perfect Finger Spin cap.

Updated : I made an even better model, slightly taller which gives more of a cup for your finger to sit in. Both caps work great so it's personal preference.