The filter covered by this specification is used for the adsorption of toxic gases and for the filtration of particulate matter from atmospheric air. It is used as part of the chemical and biological filtration system of shelters and military vehicles. The filter is part of the M93 Gas-Particulate Filter Unit which is mounted to the back side of a vehicle's shelter. It is also used in the air filtration systems of M1 series tanks and 155-mm Howitzer, M109A6. Some filters are expected to be installed in the horizontal position and others in the vertical position.