This is a genuine Girard-Perregaux automatic movement, with a hidden crown, circa 1955.
The case, dial, hands and markers are in pristine, original condition. Watch has a Brevet patent, and 17 jewels. Watch has been cleaned, and works perfectly. 43mm top-to bottom,
including the lugs, 38.5mm side-to-side.
Girard-Perregaux Gyromatic Wristwatch