Girard Perregaux Caliber GP 12.4

The Girard-Perregaux caliber GP 12.4 is a vintage handwound movement found in a Lunar Dot “Playboy” watch from the 1960s.

Technically the GP 12.X movements have a small sweeping seconds subdial at 6:00, but the watch with this caliber is a 2-hander with only hours and minutes.

The movement is signed:

Boxed Girard-Perregaux logo / GP eagle and anchor logo / Swiss / 17 Jewels / 6 digit serial number

It appears that there are no caliber number markings on the movement itself, however, this caliber is based on the AS 1640.

There are several variations, and more common seems to be the GP 12.3, with the main difference being that the 12.3 has an Incabloc anti-shock device and the 12.4 pictured here has a Kif Ultraflex anti-shock device.

Additional Resources:

• Check back

Note: This caliber listing is still being updated, but feel free to start discussions on it in the comments below…