Edited this at an attempt for an airsoft mouth cover.
I would be careful using this at a field. Make sure it's a solid piece, so 100% infill. Always check with field refs before using this.
By downloading and printing this mask, you accept any risks that may arise, and understand that I forfeit any liability from you using this mask.

Edit (11/10/17): Added air holes and slots on the sides for straps to go through