Anti-Fog Clip Attachment For Masks

Make sure that the nose clip sits right on the middle of the mask, mark the hole with some pen or you can insert the snap fastener with the peg to mark it. 

Grab an exacto knife or anything that is small and pointy (eg: screwdriver) and create a hole where the peg can enter. Insert the fastener with the peg in the front of the mask and lock it with the other part and your done.

Printed with PLA works great.