Z-offset calibration

This is my goto z-offset calibration STL. It consist of 5 rectangles 20x100 mm. It is 0.2 mm high (1 layer), for calibration when using 0.2 mm layer height. You can scale it by the z axis, to calibrate for different first layer heights.
It allows you to calibrate z-offset using babysteps. Nothing fancy, but helps me a lot when calibrating for a good first layer.