Great derivation of an amazing design, I wanted to fit the helmet in my car, so I did! Thank you Replicator 2 and thingiverse for allowing such a thing to happen
This is designed to fit a gear shift knob for a Chevy Aveo 2005, or a sphere gear shift knob of 50mm diameter. It should just push on with a little force, and shouldn't have too much play to move around much.
The original file is on tinkercad if you want to play with it and fit the hole a little differently: https://tinkercad.com/things/b4yVTZtfZfv-daftpunkhelmet