The SAS Safety 2985 Non-Toxic Dust Mask box of 50 masks is certainly inexpensive. Unfortunately, their quality is proportional to their cost. I got the masks to filter out the dust of scoopable cat litter. The masks filter out some dust but, even after adjustment and trying multiple positions for the mask & head strap, they do not fit snugly to my face and so allow dust through spaces between my face and the mask. I've also noticed that, even when the mask is fitted more snugly than usual to my face, the litter dust comes through the mask to the point where it's visible around my nose after I take off the mask. The mask does filter out some dust. My asthma hasn't been as bad with the masks as without. However, the masks allow enough dust through that I'm still smelling and tasting it while scooping the litter. Since they have some function and are inexpensive, I'm giving the masks two stars.