My Volvo XC90 has 19 mm lug bolts which came with silver plastic caps. When I changed over to new wheels I wanted black caps to better match the wheels. These are a remix of the 17 mm caps posted by balky, just scaled up. They fit snugly but can still be removed with the nut cap remover. A set of 20 caps used about 90 grams (30 meters) of 1.75 mm PLA filament and printed in about 10 hours.