This is another GP automatic. According to the advertisements in 1957 and the information feom the internet: "The Gyrotronic is the invention of a Swiss horological engineer and represents an entirely new solution to an age-old technical problem. It combines with almost incredible simplicity such intricate functions as: Roller-Bearing, Free-Wheel, Automatic Clutch and Rotation-Inverser." "The Gyromatic transmits energy of every movement to the mainspring without any loss. The very first milligramme of energy automatically pinches the rollers of ruby transmitting that energy to the mainspring.". They even state: "The scarcely perceptible movements of a person aspeel suffice to wind up the watch automatically."
The 39 jewels Gyromatic is the most iconic vintage GP watches from the 1950s -70s. The watch is in very good condition with an original metal bracelet and the crystal dial and winding crown. I have traded my Casio metal plus another watch for this watch.There are some versions without the GP raised logo. In this watch, I was told that the raised GP & The markers are solid gold.