73150393
Dec 1, 1977
Aug 1, 1978
AUDIO-VISUAL PROJECTION UNITS COMPRISING PROJECTORS, VIEWING SCREENS, AUDIO AMPLIFIERS, AND COMPONENTS AND ACCESSORIES THEREFOR-NAMELY, INTEGRAL AUDIO SYNCHRONIZERS, SCREEN ATTACHMENTS FOR SHOWING MIXED HORIZONTAL AND VERTICAL SLIDES, JACKS FOR EXTERNAL SPEAKERS, PROJECTION LENSES AND FRONT PROJECTION ATTACHMENTS
Electrical and Scientific Apparatus