Textured face seal prevents slippage and improves comfort. The enhanced valve will reduce exhalation breathing resistance for improved comfort while breathing. The mask is maintenance-free as it has an integrated cartridge and integrated filters. All featured masks have 10 x workplace exposure limit (wel) or 1000 ppm (whichever is lower) for gases/vapours and 10 x wel for particulates. Mask types 4251 and 4255 protect against water-based mists, organic gases and fine specks of dust or oil. Mask type 4279 also protects against ammonia gases, inorganic gas and acid gases. all masks conform to en405:2002. Includes a re-sealable bag for hygienic storage and transportation. The low-profile design won’t hinder your peripheral vision. Filters should be disposed of when saturated or within one month.