I needed a miniature spanner to hold a lock nut in place when replacing the elements of a Dualit Original toaster.  The instructions provided say use a 6.5 mm spanner which is not in my metric set.  Fortunately a little bit of CAD and 4 minutes printing time with my Prusa and this a allowed me to complete the job with a ¼ inch socket to tighten the final nut.

The model is slightly over sized to allow for shrinkage.  My spanner printed on a Prusa i3 mk3s measured 6.4 mm flat to flat on the C which fits easily over the ¼ inch brass nut (6.35 mm).

I printed the one in the photo in Prusament Galaxy Silver PLA.