Patek Philippe Calatrava ref.3520, white gold bracelet watch, ultrathin, made in 1968. Cal.175, 9 ligne (20.8 mm) wide, 1.75 mm high, 18 jewels, manual winding, stamped with the seal of Geneva. Silvered dial, signed. 32mm, screw case back. 18k white gold bracelet and clasp. Accompanied by the Extract from the Archives.