Features: The use of food-grade high-quality materials, , , and , men, women, and children can rest assured to wear. Activated carbon and electrostatic filter double protection, and can be used freely, suitable for people with high air quality requirements. Applicable scene: suitable for formaldehyde, benzene, secondhand smoke, automobile exhaust, haze, and other harsh environment and heavy pollution weather protection. Family mixed-size package, each with a pair of S-and M-L sizes, with a built-in filter and an additional two pairs of replacement packages. Easy to carry, equipped with mini storage box, easy to wear at any time when you are away from home, there is no need to worry that there is no place to store it. Specification: Item: Invisible Nasal Filter Material: Silicone,ABS Shape: Narrow; Round （Optional） Narrow Size: S: 9*15mm; M: 11*16mm; L: 11*19mm Round Size: S: 11*14mm; M: 12*14mm; L: 13*15mm Package Size: 8.5*4.5*4.5cm / 3.35*1.77*1.77in Package Weight: 35g / 1.23oz Package List: 1 * S Invisible Nasal Filter 1 * M Invisible Nasal Filter 1 * L Invisible Nasal Filter 3 * Replacement Filters 1 * Tweezers