Tabbed edge allows operator to easily tear off worn lenses while on a blasting job, reducing down time. For optimum protection always use inner and outer lenses. In addition, using genuine lenses provides further protection. This is because non-OEM lenses are often non-conforming with NIOSH standards. Dimension – 13″x 5″. Thickness – 0.010″. Mylar material. Comes in pack of 25 pieces.