This is the Casio TM-100 Transmitter Watch, a rare piece of technology released in 1987 that became a groundbreaking innovation, arguably ahead of its time.This wristwatch featured a built-in FM radio transmitter, complete with its own antenna and microphone. With this "small" device, you could turn yourself into a portable radio station anywhere, allowing anyone with a radio receiver within a range of up to 100 meters to hear you.Credits: Inventos y Genios Brillantes