Procedure Mask McKesson ASTM Level 1 Earloops Child Size. Soft, lightweight material for cool comfort; comfortable knitted earloops for a custom fit on small facesFormable nose wire forms a snug seal for increased protection; spunbond outerlayer material helps provide protection against fluidsBacterial filtration (BFE) and particle filtration efficiency (PFE) greater than or equal to 95%Meets ASTM F2100-19 Level 1 requirementsIntended to be worn by children ages 4-12 years old with appropriate adult supervision.