I designed this mask strap from scratch on TinkerCAD, and took cues from the highly popular mask strap remix. There are a few differences:
1) Oval shaped, filled center section in the center instead of trapezoidal with a hole. This is so that you can quickly and easily edit the center section with your own lettering and logos, stencils, labels, and stamps - to more easily market the straps for sale in your area to businesses and also individuals.
2) Three hooks for the elastic straps instead of four, and they are marginally closer together. I have never seen anybody need to use the two innermost hooks on the most popular version of the mask straps on Thingiverse, and this saves a small amount of material (makes up for filling in the hole a bit) and also allows for more accurate tension as per user preference on most heads.
3) Hook ends are very slightly ovular instead of circular. More grip on the bands.

I print these in PLA. They can be printed with a 1.0mm nozzle at draft layer height, but for adding in lettering and logos, I usually aim for 0.6mm nozzle and 0.2mm layer height, or else the added letters and logos often have portions that are too fine to print properly. Should take about 20 minutes per strap with a 0.6mm nozzle. Infill is not important, since it is very thin.