The 4 Ply Surgical Mask is ideal for medical professionals or people working in high-risk areas. The extra layer adds another level of protection which increases the bacteria filtration efficiency compared to the 3 ply surgical mask. The 1st and 4th Layer of 4 ply Surgical Mask are Non-Woven Spun Bond Fabric. The 2nd Layer is 40 GSM 100% Polypropylene Melt blown and the 3rd Layer is 25 GSM 100% Polypropylene Melt blown. The PFE >99 (Particle Filtration Efficiency) and BFE (Bacterial Filtration Efficiency) for the mask exceed 99%. The mask comes in packs of 10 in airtight Rhysley packaging. The elastic ear loops which enable to use them for a long period, the built-in nose piece molds itself to the face design to ensure a perfect fit for men and women The face mask comes with a smart pulls dispenser box which makes it convenient to pull up a mask and re-pack the box back to preserve other masks in good condition ASTM F2100-11 Standards: ASTM Level 3 Mask