I broke the strap buckle on a pair of spike sandals and needed a replacement. I found many alternative designs - all of which were either weak and broke again, or didn't grip the strap sufficiently to be useful.

This re-design addresses those issues and additionally has a finger relief to make the release process easier. The flat face and finger relief should be on the strap side when fitted.

I printed this in PLA at 0.32mm layer height, 4 perimeters, 15% infill without supports.