McKesson ASTM Level 1 Medical Face Masks are constructed of a three-layer, non-woven fabric featuring a spunbond polypropylene on the inner and outer layers and a meltblown polypropylene middle layer. These masks meet the ASTM requirements for level 1 barrier protection. McKesson ASTM Level 1 Medical Face Masks are designed to fit most users and feature bacterial and particulate filtration efficiencies greater than 95 percent with a fluid resistance at 80 mm hg; a dual-sided design with a blue outer layer and white inside that promotes proper use, convenient donning, and style preferences; a flexible, metal nose-bridge bar which bends to fit the users unique facial contours; and single-strand, elastic ear loops designed to be low-profile and stretch to enhance comfort and fit with less irritation.