New Thermally Reactive Advanced Protection (TRAP) breathers eliminate moisture from hydraulic reservoirs. The breathers contain a porous thin-film network coated with water-absorbing chemicals. The resulting high-surface-area absorbent rapidly removes water vapor from air while minimizing size and weight. TRAP breathers remove atmospheric moisture at only 15% relative humidity and expel moisture with every flow cycle, regenerating water-holding capacity and giving long breather life. The open-porous structure minimizes restrictions and does not impede airflow. The breathers are available in ABS plastic and epoxy-coated steel, with NPT, BSP, and bayonet connections and an optional electronic indicator.