3 layers structure: non woven fabric, high density filiter layer, skin friendly composite fiberColor: blue onlySize: 7 * 3. 74inType: disposable masks for dust protectionFunction: this 3 layers disposable mask can easily stop water seepage provides a better ability to block fine particlesPls be noted: this is a disposable mask, the protective effect lasts 8-10 hours, avoid continuous use for many days, you must destroy and replace the new mask after used