This is a simple 100mm calibration object that will deliver more accurate results than the standard 20mm calibration cube.
The formula is:
Calibrated steps = current steps * 100 / measured axis (mm)
On first print of device, the x axis measured 99.15mm. I used the EEPROM Marlin Editor Plugin to get my x axis is 79.10 steps/mm. Using the above formula:
79.20 * 100 / 99.15 = 79.88 steps/mm
I entered the new value in EEPROM and printed the device again, with the new x axis measuring 99.95mm.
Double check the device orientation and axes labels in your slicer, but the model model should import correctly oriented.
The easiest way to adjust Steps is with OctoPrint's EEPROM Marlin Editor Plugin