Calibration cross
thingiverse
You'll need a calibration strip that's precisely 150 millimeters across to fine-tune the accuracy of your printer on both the x and y axes.
Download Model from thingiverse
With this file you will be able to print Calibration cross with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Calibration cross.