This is a great anti-fog for goggles, masks, sights and sunglasses. It also provides a this anti-scratch layer to help protect your optics. I have been using it for years on rifle scopes and sunglasses and love this product...worth many times its $4 price tag. Scope Dope is the same product marketed to a different niche, the compound is the same. I have found that using multiple applications on both sides of the lenses produces the best results.