Abstract: A unitary gasket component is designed to provide a complex acoustic path for bringing sound to a microphone. The path includes a pre-plenum and apertures to allow external sound into the pre-plenum. The path further includes an acoustic filter communicating with the pre-plenum and defining relatively small openings for sound to exit the pre-plenum. A voice tube extends from the acoustic filter to a microphone plenum, the latter being in direct communication with the microphone.

Abstract: A flat, substantially transparent lens lying in a flat plane retains a designation card within a recess in a surface. The lens is made of flexible sheet plastic with means at either end for securing the lens in the recess. At one end, a tab is integral with the lens and has an attachment end which joins the lens. The tab extends away from the plane of the lens to a geniculation spaced from the lens plane. At the geniculation, the tab reverses direction and extends toward the lens plane to return generally to that plane, where it terminates in a finger grip.

Abstract: A flat, substantially transparent lens lying in a flat plane retains a designation card within a recess in a surface. The lens is made of flexible sheet plastic with means at either end for securing the lens in the recess. At one end, a tab is integral with the lens and has an attachment end which joins the lens. The tab extends away from the plane of the lens to a geniculation spaced from the lens plane. At the geniculation, the tab reverses direction and extends toward the lens plane to return generally to that plane, where it terminates in a finger grip.