Features: 1. PM2.5 valved mask dust respirator mask washable reusable face masks cotton unisex mouth mask muffle. 2. Soft, warm, breathable, windproof, sweat absorption and skin friendly, keeps your face dry and comfortable. 3. Breath valve design. The same position alternates twice, it reduces heat and moisture accumulation, small air resistance, smooth breathing. 4. Ergonomic nose and loop can be adjusted to fit with elastic ear strap, more comfortable to wear. Specification: Material: Cotton Applicable: Adult Size: One size(adjustable) Color: As the pictures show Function: Against PM2.5, anti-fog and haze, industrial anti-pollution, anti-vehicle exhaust, dust, secondhand smoke, pollen allergy, keep warm, etc. Note: 1. Please allow tiny size deviations due to human measurement. 2. Due to the effect of light and monitor's brightness, there may be slight differences between the color tone of the photo and the actual item. Tips: 1. The plug-in filter cannot be cleaned, and it is usually replaced every 7-10 days. If air pollution is severe, replace it every 3-5 days. 2. If there is a lot of dirt or sticky sediment on the filter film, please replace the filter. 3. Do not use if inadequate ventilation, poor breathing or sleeping. 4. Not recommended for children under 2 years. Cleaning method: 1. It is recommended to dilute with neutral detergent and water, and then clean (please remove the filter before cleaning). 2. Do not soak in washing liquid or water for a long time, and do not use bleach. 3. It is recommended to clean once 1~2 weeks. Package Content: package 1: Dustproof Mouth Mask package 2: 4 x PM2.5 Mask Replacement Sheet package 3: 10 x PM2.5 Mask Replacement Sheet package 4: 20 x PM2.5 Mask Replacement Sheet