This stepped cylinder allows you to check 4 outside diameters in the X and Y directions, and 4 heights in the Z direction. Diameters ore 1.00", 0.75", 0.50", and 0.25". Heights are 0.25", 0.50". 0.75", and 1.00" The top surfaces of the cylinders are inscribed with lines. Line these up with the positive X and Y axes so you can keep track of them after the print is removed from the printer. It is designed with a brim so it won't lift off of the build platform. The brim doesn't interfere with the measurements, but I usually trim it off anyway.