This is a simple ear protector to be used when wearing a mask. The double-strap has a tendency to slide down a bit. However, if you have a pony-tail, you can stick it through the hole to keep it in place.

It was designed to be printed with Nylon, which is more flexible than PLA. If you are printing in PLA you may want to reduce the thickness a bit. This can be done easily in cura by moving the model down in the Z-axis into the build plate. Also, I suggest upping the number of walls to some large value as it will result in a stronger print.