1. It is not recommended to use this product under the condition of low oxygen,heavy air polution, poor breathing or during sleep.2. For patients with severe asthma or other severe respiratory diseaases. please use with caution.3. Please use the masks properly. Do not modify or misuse it at will to avoid serious consequences caused by improper usage.4. Store in an enbironment with the temperature of -20°C to 38°C and the relative humidity of the environment shall be lower than 80%.