I bought it for a 3m mask so that I could wear it with a filter. I bought it because other inexpensive glasses, when working with a perforator, let the flying paint through a little (to the eyes). I hoped that the new glasses are more dense. I'm not sure if it's better, but it might be. Haven't tested yet. Pros below: light and quite comfortable. Compact there is some protection against fogging Not much strain when wearing. With its cons: Of course there is fogging, but less than in ordinary glasses. I'm not sure that they sit so tightly - nevertheless, the fit is not complete and not perfect