For the protection of particulate matter and acid gas odor (such as sulfur dioxide, hydrogen fluoride, chlorine) cold flow exhalation valve is equipped with the 3M patent, suitable for long time wearing damp heat environment. S estions for glass products, chemical industry, papermaking, donkey smelting, brewing industry.1. check the mask before each use and make sure it is in good working order. Check all parts of masks, including two rope, nose clip and screw fixation, found damaged or missing parts should be immediately discarded masks.2. correctly wear a mask, and then check the tightness of the mask and face after wearing a mask3. please discard and replace the new mask when the respirator is damaged or the respiratory resistance is too large