Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5019203.

The original is published by TH3D Studio LLC. https://github.com/th3dstudio/UnifiedFirmware/blob/2.0.x/STL%20Files/Gantry%20Leveling%20Block%20STL/GantryBlock%20-%20print%202.stl

In Ender3 it was changed to 12 cm. Fits in the groove of the 4040 aluminum frame.