Rolex 2508 chronograph, ‘30s 18k gold round case, n.38313, case-back engraved with monogram, olive pushers. Black dial, multi-scale, painted indexes and arabic numerals. Hand-winding movement. Leather strap. Size: 37 mm. Notes: Launched in the mid 1930s, reference 2508 was Rolex's very first model to feature two chronograph registers, as well as two buttons to operate the mechanism. The reference can generally be divided into two series: while models from the first generation feature olive pushers and a larger case size, second generation specimens feature rectangular pushers and a relatively smaller case diameter.