😷 The Universal 4521 mask is 2 layers of 100% cotton fabric that provides a comfortable barrier against airborne irritants. The 4521 comes in many colors and three sizes: The SMALL size fits most children and smaller adults, the MEDIUM size fits most teens and average-size adults, and the LARGE size fits most larger faces, including large teenagers. | 😷 The Universal 4521 mask is made from two layers of different density cotton: the black outer layer is less dense (21S), designed to block larger particles. The white inner layer is denser (26S), designed to block smaller particles. Both layers are extremely soft and are designed to help disperse moisture, making the Universal 4521 comfortable for daily wear all day long. | 😷 The Universal 4521 mask can be washed by hand and hung to day, or washed with a normal load of laundry in warm water and tumble dried on a medium heat setting. The mask can shrink slightly if it’s washed or dried in high heat, but it easily stretches back to form with a few firm tugs at the top and bottom of the mask. | 😷 The Universal 4521 mask is unsex and designed to fit almost all face sizes. It has stretchy elastic ear-loops and an adjustable nose bridge that provides a close but comfortable fit with minimal gaps. With a snug fit, the chances of unfiltered air entering or escaping are minimized. The snug fit around the nose bridge helps to greatly reduce the buildup of fog on your eyewear. | 😷 The Universal 4521 is ideal for many daily activities, including but not limited to: running, walking, jogging, house cleaning, dusting, yard or garden work, and much more. It protects your mouth and face from dust, ash, pollen, grasses, passive smoking and other airborne pollutants. (Note: the Universal 4521 is not NIOSH approved. It is not for use against silica, asbestos or other harmful substances.)