These are definately not able to stop glasses fog
I purchased these thinking they were double side adhesive and that is how they would work.  As is they are an incredibly thin spongey material that simply sticks to the mask.  They are not moldable and there is literally nothing about them that would prevent fog.  I tried these at the same time as the metal moldable nose bridges i purchased separately.  This stopped no fog at all compared to a mask with the metal nose bridge and the mask with neither.  I'm about to request a refund.
Rating: 1 stars