2000 Series Reusable Respirator Particulate Filters are designed to fit a wide range of 3M half and full-face reusable masks with the bayonet-style connection (except 6098 and 6099 which are full face only). Polypropylene composition. Features and Benefits Flexible to fit comfortably under welding shields Lightweight with low breathing resistance Typical applications Protection in hazardous environments Notes 2125 - Protects against solid and liquid particles 2128 - Protects against solid and liquid particles, ozone protection(10 x OEL), nuisance level organic vapours/acid gas 2135 - Protects against solid and liquid particles 2138 - Protects against solid and liquid particles, ozone protection(10 x OEL), nuisance level organic vapours/acid gas Depending upon your need, there are six families of filters to choose from Standards EN 143:2000 + A1:2006