This Model is designed to calibrate your 3D-Printers X, Y and Z axis. The cutouts are 20, 40, 60 and 80mm from the end of the model. The entire Model is 100mm on all 3 axis. With the measurements you can determine how you have to adjust your E-Steps on each axis to improve your printers accuracy.
If you have any suggestions to improve this model, please let me know.