Moldex Airwave™ N95 Disposable Particulate Respirator, Oil Free Particles, Medium Large ORS NASCO flat on opposite Flat sides of flat on opposite Flat sides of all half round files are double cut Backs of all 4 in and 6 in files are single cut Backs of all half round second cut files are longer than 6 in are double cut 0118 in Bristle Material Steel Catalog Big Catalog Construction Catalog NO Country of Origin US Dia Larger surface area means more air flows in and out of the mask without a valve Durable Dura Mesh® shell prevents collapsing from heat and humidity FlexFit® design fits the contours of the face and mouth for comfortable extended wear Soft foam nose cushion and pinch free nose bridge