3D-printerbed calibration

This nice printerbed calibration is designed with FREECAD. I have designed this for my Craftbot Plus printer but it can be used for every 3D-printer ofcourse. You can use and adapt this design for your own needs. I have added the Freecad-file also.

The original size of my design was for a 250x200 printerbed, but because I use a glass bed I have made it smaller: 190x140. Overall thickness is 2mm. The thicker calibration tabs are all 5mm.

How to use it:
Just print it and measure the heights in all corners to see if they have the same height. Also look at the flat surfaces: they must be looking good and flat too.
Adapt your bed if needed and print it again if you like.