Pros:
- weight is born on the nose and ears instead of relying on a strap; although there may be a strap on the back of this unit; I can't tell -- the sunglasses approach eliminates the need for a second part or fitting
- there is a single fixation point for the mylar sheet (12x12" it looks like)
- If the sheet could come off easily you could toss both into a tub of bleach and reuse these
Cons:
- the front of the mask is very bent; which will cause more glare; it would be better if it had more of a flattened apsect in the front
Reference:
All the files & instructions:
https://github.com/GliaX/faceshield