Made for a jeep wrangler TJ with 5 speed transmission. Has a 10mm hole which will thread itself when you first screw it in, Will post pictures when I print final design!
Madde for .a JK wrangler with 6 speed transmission. Ball diameter is 70mm, with a 12mm hole in the bottom. I use it with this shift knob adapter from amazon since the JK stick is notched. https://www.amazon.com/gp/product/B01MXHDJW2/ *note I also had to make the center hole a little larger since it didn't quite fit on the stock jk stick
It is a rather large ball, very comfortable for me to hold though, all the other knobs are just too small for me to grab comfortably.
I use 20% infill, feels pretty stable, could probably go down to 15 though
Hope you like!