The camera is the worlds first sound on film camera. According to Coe the RCA-Victor sound camera was announced in 1933 but did not become generally available until the autumn of 1935. The camera was recorded sound directly on to the film whilst filming. The sound track was recorded by a light beam from a battery operated lamp refelcted from a small mirror attached to a diaphragm vibrated by speech from the camera operator. The microphone grille came close to the photographer's mouth in the filming position.