These non-medical, washable face masks are intended to provide a layer of protection. There is a pocket to add a filter for a little additional protection. This mask is not a suitable substitution for a surgical or medical mask.There is a plastic covered wire in the top seam to help mold the mask around the ear. These masks are one size. I have not tried them on a child, but they fit teens to adults.Please do not cut up vacuum filters to use as inserts. Kleenex, coffee filter, or paper towel are suitable materials for additional protection inside the pocket. Remove any filter material before washing. Mask is made from 100% cotton with braided elastic.