The Kimberly-Clark 62470 Kimtech M3 Sterile Pleat-Style Face Masks (20 / Pack) offer excellent bacterial and particle filtration efficiency with post-sterilization BFE of 94.1% at 3.0 micron and 89.3% PFE at 0.1 micron. Featuring knitted earloops and a fully enclosed, soft, bendable nosepiece. Made of a low-linting polyethylene outer layer and a soft inner-facing fabric, Gamma irradiated with a Sterility Assurance Level of 10-6. Recommended for ISO Class 3 and higher clean room environments