Excellent Design: Adjustable elastic ear straps and built-in nose bridge can perfectly fit the face; breathing valve unidirectional air out, keep the face dry and fresh, comfortable and have a good sealing effect. High Quality: The product is made of high quality materials. Each filter consists of 5 layers of material, including 2 layers of non-woven fabric, 2 layers of melt-blown nonwovens and 1 layer of activated carbon. Protective Effect: The protective measures composed of breathing valve and filter can effectively protect you from pollutants such as harmful dust particles, PM2.5 particles, and fumes. Packaging & Size: This product includes 4 black mouth covers and 200 filters. The mouth cover's size is 7.5in×5.5in, the filter size is 4.72in×3.14in. Note: The mouth cover can be reused after washing,while the filter cannot be cleaned, it is recommended to replace it daily to achieve the best protection. 4masks&30filter（masks*4,filter*30） 4masks&50filter（masks*4,filter*50） 4masks&100filter（masks*4,filter*100） 4masks&200filter（masks*4,filter*200）