Size S: Kids size??6.9*5.1 inch??, Size M:adult size??7.9*5.9 inch??. Equipped with two activated carbon filters with replaceable 5-layer protection, M-shaped nose clip. 5 layer activated carbon filter 4.73*3.15 inch. Effective against dust and low level odor,It??s comfortable but still offers the full protection you need. It’s adjustable around the ears so it can fit as loose or as snug as you want. The buckle can adjust the elasticity, and you can change the length according to the contour of your face to prevent leaving marks on your face. Protects your mouth and face from dust, cold, haze, exhaust emissions, passive smoking, easy to breathe through.