This is a remix for @Cewo Nut for Drill Stopper with flattened sides for 22mm flat wrench. Please visit his profile to get rest of parts for this Drill Stopper.
Flat sides are generally easier to grab. Helpful if the nut would get stuck on a drill. With width of 15mm you can additionally take the nut off with use of flat wrench if it's really stuck.
The author remixed this model.
Flattened sides of the nut so it can be grabbed with 22mm flat wrench. Flat sides are generally easier to grab. Helpful if the nut would get stuck on a drill.