Apollo Command Module LiOH Filter Assembly, 7.25″ x 7.25″ x 5.25″, bearing an affixed Airesearch label on the side, reading: “Absorber Element CO2, Part 813-540-2-1, Serial 118-360, Order NAS9-150, NASA 004000118360, Ref Spec ME901-0218-0051." The side is stenciled with red text: “Ground Test Only.” Includes its original plastic packaging. In fine condition. This lithium hydroxide canister was designed to maintain a pure-oxygen environment within the Apollo spacecraft; utilized as part of the Environmental Control Unit (ECU), this assembly used LiOH to absorb carbon dioxide and a filter to trap particulate in the circulating air.