| 摘要 |
A respiratory protection device for protection against airborne toxic material comprising a rigid tube having an inlet opening at one end, an outlet opening at the opposite end, a filter for particulate material at the inlet opening, two distinct layers of gas adsorptive material which are arranged in series between the inlet and outlet openings, and means for retaining the layers of adsorptive material within the tube. The chemical composition of the layers differ from each other and the compositions have different adsorptive characteristics.
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