3PLY-4 PLY (Medical Use) 1. Non-Sterile Disposable with a leak-proof coated nose clip and non-latex ear loop elastic 2. Size: 178 mm x 98mm 3. High Bacteria Filteration. Three Layer with Non-woven fabric Middle Layer. Outer Layer Bacteria Filteration efficiency >95%, inner layer bacteria filteration>80%. Low Breathing Resistance Delta P