Allister Mask Sword and Shield Gym Leader 3D print model
This mask contains two bars on the inside that can be used to attach straps.
For the eyes and mouth, use black fabric that you can see through and affix it to the inside of the mask.
The mask was designed for pupils that are about 3 inches apart. The large eye holes give a tolerance of about plus or minus half an inch. It can be resized up and down pretty reliably if you need to resize it.
The mask is approximately 220 mm x 220 mm x 33 mm. The space within the bars is approximately 158 mm wide.