Delta Calibration Check Rings.

180mm is the largest ring, 0.8mm width, 0.5mm high, 20mm apart. Centre disk ends up being about 13mm across. With a 0.4mm nozzle this should give two passes for each ring.

Depending on layer height and other slicer settings it should only be one layer. Scaling layer height or the model scale in the z axis will allow you to get a single layer.