1. It is made of high-quality imported silicone rubber and suitable for facial features. 2. It won't be aging, hardening but comfortable and durable. 3. Sealing edge of contour line and head belt eliminate discomfprt caused by the oppression to facial nerve. 4. The design of nasal part fits well with the nose, which limits breath of exhaust and increases comfort. 5. Comfortable, durable silicone skirt design, ftve points head belt, anti-fog design of standard nose and mouth cover. 6. The sizes which can meet almost all type of faces and do not leak.