The MCU-2/AP Chemical–Biological Mask is used by the U.S. Air Force ground crews and aircrews when not in flight as well as the US navy, US Coastguard and FBI. This protective mask is constructed of molded silicone rubber facepiece material, and an integral, molded, polyurethane, one-piece panoramic lens is bonded to it. Filtration is provided by one C2A1 canister mounted on either side of the facepiece. The primary voicemitter is located over the mouth area with a secondary voicemitter in the cheek area to utilize telephone handsets.