Scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signaling, checking apparatus and instruments, namely; intercom systems comprised primarily of a power supply, intercom main stations, intercom substations, relay boxes, plug boxes, headsets, handsets, loud speakers and rotary lights; intercom systems comprised primarily of a power supply, intercom main stations, intercom substations, relay boxes, plug boxes, headsets, handsets, loud speakers, rotary...