Flat bottom adapter for MX switches. If you need a "flat top" variant, check out this model instead. Also only 1u keys are supported.

The Blender source is built non destructively and should be very easy to further modify.

By default, the adapter has a 1.3 degrees counter rotation to offset the inherent stem twist, which, for whatever reason, happens on the MK4S, and probably other printers. If you need a straight stem, us the No Counter Rotation variant.

Confirmed good fit with PLA at 0.15mm resolution, 100% infill.