Rolex - Ref. 3131 - Pink Gold - Bubble Back Rolex, Oyster Perpetual, Chronometer, case No. 550283, Ref. 3131. Made circa 1945. Fine, tonneau-shaped, self-winding, center seconds, water-resistant, 14K pink gold wristwatch with a gold-plated Rolex buckle. Three-body, polished and brushed, polished inclined bezel, screwed-down case back and crown. Silver with applied yellow gold Arabic numerals, outer minute divisions. Steel baton hands. Cal. 9 3/4, rhodium-plated, straight-line lever escapement, monometallic balance, self-compensating balance spring. Dial, case and movement signed. Diam. 32 mm. Thickness 13 mm.