Included are knobs for the 5 most common sizes of nuts and bolts in Metric: M6, M8, M10, M12, M16. Though you could scale them to other size bolts.

On my old printer I had to print with a brim, but with my bambu A1 I am able to print with no brim on both textured and smooth plate.

I tend to abuse these putting them on shop tools, or using them outdoors. So, I usually print with PETG, thicker shells, and denser infills. I have a set that I have been using outside on my chicken coop in the PNW for three years, and they are still going strong.