Replacement filters for your Fridaze brand 100% wrinkle-resistent linen mask. PM 2.5 filters are made of activated carbon and non-woven melt-blown filter cloth, adding additional filtration and protection. Ideal to protect your mouth and face from dust, haze, germs, allergies, smoke, pollution, ash, pollen, gardening and craft particles. The filter slides easily in and out and is recommended to be changed 1-2 times a week, depending on usage. The PM 2.5 filter’s air resistance will increase over time as the spunbond fibers accumulate airborne particles, making it noticeably more difficult to inhale. When this happens, the filter should immediately be removed and replaced. Replacement filters are sold in a pack of 10.