WoodyKnows Super Defense Nasal Filters, Reduce Pollen, Dust, Dander, Mold, Allergy Relief, Air Pollution PM2.5/10 (Slotted Nostrils, S(6 Frames)) There are two shapes of nasal filters for your choice, round shape and slotted shape. Please choose it according to the shape of your nostrils. The size of nasal cavity is different from size of nose. First-time buyers are highly recommended to order the multi-size pack(S/M/L/XL) to find the most suitable size. S/M/L/XL(Round Nostrils)=I-R/II-R/III-R/IV-R S/M/L/XL(Slotted Nostrils)=I-S/II-S/III-S/IV-S Remove a pair of filters from the silver plastic bag. One side of the filter is net and the other side is fiber. Install a pair of replacement filter into each frame with its net side facing you. Then install the black retainer ring into each frame. The filter and black retainer ring should now be secured by the frame tabs. Done. Your nasal filter is now ready for use. Positioning - Holding the frame of the nasal filter with the narrow ends pointing towards your nose tip, the wider ends pointing towards your face, and the connector pointing down. Insert - Using your fingers, insert the filters into your nostrils until the bottom of the frame is positioned just inside your nostrils. Adjust - Adjust the filters into your nostrils with little fingers. Done - You are ready to breathe clean air. 6 pcs frames,6 pairs pre-installed filters,6 pairs spare filters Others: Tweezers, Storage Case, Manual