This Rolex reference 2508 chronograph was produced circa 1946. Back in the day, its 35mm diameter by 12mm thick case was massive. Original "ANTIMAGNETIC" dial with both telemetre and tachometre scales, arabic numerals, and original rose gold hands. The case is unpolished with its original finish and legible serial number (521XXX) on case back. 

Original untouched dial signed ROLEX CHRONOGRAPHE ANTIMAGNETIC with telemeter and tachometer scales, arabic numerals and indices, two subdials (one for constant seconds and the other the chronograph 30 minute totalizer). Both subdials are slightly sunken and have concentric guilloche. 

Original manual winding column-wheel chronograph Rolex Caliber is an improved Valjoux caliber 22 ebauche. Vintage chronograph collectors know that the Valjoux 22 is one of the all-time great two-register chronograph movements. The chronograph hands accurately reset to their zero positions.