Fitted nose piece to ensure proper fit. 3 layers of breathable non-woven fabric. Easy to put on with round elastic ear loops. Latex free. 98% bacterial filtration efficiency. Sub-micron particulate efficiency at 0.1 µm >= 98%. Resistance to penetration by synthetic blood at 160 mmHg. Class 1 flame spread. These masks should be disposed after each use. Box of 50. Blue. ASTM 2100 certification.