1940s Rolex Oyster Perpetual Chronometer Bubble Back 14k Yellow Gold Arabic dial 3131The 1940s Rolex Oyster Perpetual Chronometer reference 3131, known as a Bubble Back, is a quintessential early automatic Rolex that helped define the brands reputation for precision and innovation. Cased in 14k yellow gold, it carries a warm vintage presence, enhanced by the signature rounded, protruding caseback designed to house Rolexs thicker self winding movement. There was a time when the early Bubblebacks were the hottest Rolex watches on the