Waterproof/breathable fabrics resist liquid water passing through, but allow water vapour to pass through. Their ability to block out rain and snow while allowing vapour from sweat to evaporate leads to their use in rainwear, waterproof outdoor sports clothing, tents, and other applications.
Waterproof featuresWashable and reusable cotton mouth mask,comes with 4 PCS PM2.5 carbon replaceable filtersAdjustable elastic earloop and M-shaped nose clip for a comfortable fit,allows for easy breathability5 layer activated carbon filters,cares for your skin keep fresh.Recommended replacement of 1~2 times a weekThe mask works like a active natural shield against any pollution like dust, germs, allergies, smoke, pollution, pollen, cold, flu and keep you safe and healthyOne size fits mostPls wash & dry the washable face mask before use.Attached the blue color filter to the inner side of the face mask with the double-sided adhesive tapes.The material used for the filter is the same as the ordinary disposable face mask.