This is a handy tool to quickly measure the holes in washers, or any hole really. I keep one near my drawers, so that I can easily sort washers into their respective sizes Its in metric (sorry USA colleagues) and measures from M2.5 to M14 The tip is 2.5mm.. And then it increases to 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm and finally the outer body 14mm. I originally planned to put numbers on each ring, but struggled to do it and never went back to try... But this is something I plan to do so I have marked it as a work in progress.Print with 100% fill for maximum strength.. I use a brim as the base is relatively tall for its base.