Hexagonal bolts and nuts mini gauge

Sometime it's hard to measure in place large bolts and screws, so this little gauge can help you! Simply putting it near to the nut or the bolt head, you can read the screw diameter. It's made for metric screws, from M16 to M39 (the ones I needed). I added a 4mm negative cilynder to create a little hole. You can move or disable it. I printed it in PETG and the profile is made to reduce stringing.