Hold the end of the strap with both hands, pull the strap as far as possible, so that the mask can completely cover the upper nose and mouth area, connect the fastener behind the neck, and seal the mask with the face. 2. Pull the end of the strap and tighten it further. 3. Before use, check the mask to determine whether it is properly sealed. 4. During the use process, when the user smells the odor or the inhalation resistance increases, the service life of the filter cartridge has expired, please replace the filter cartridge or cotton immediately. User Special Considerations 1. Please do not use this mask if the oxygen concentration is below 18%. Package Includes:- 1 x Mask – 2 x Filter cover – 2 x Cartridge – 2 x Cotton filter