This Girard‑Perregaux Gyromatic dates to the 1960s and pairs classic mid‑century proportions with an uncommon Schmitz Frères four‑screw “Clamshell” waterproof case construction. The dial shows an even vintage tone with applied baton markers beneath a period acrylic crystal, while a clean unsigned crown preserves the era’s aesthetic. Power comes from the automatic Gyromatic architecture (39 jewels, ~18,000 A/h), freshly serviced in 10/2025 and delivered with a service certificate. For a contemporary collector, the watch offers historical mechanical character, documented servicing, and a confident period presence on the wrist.