The images are self explanatory, there's an extra STL for block modifier if you want to disable fuzzy skin inside.
You'll need a DC Jack and a round rocker switch.
I did this for the SK90c module but probably the it'll work SK90 SK40.
Enjoy leave feedback. Thanks!
| back.stl | 336.6KB | |
| front.stl | 125.7KB | |
| fuzzy_skin_modifier.stl | 23.3KB |
