Cosmograph Daytona Pre-Daytona 6238

Early-1960s pared-down successor to the 6234 and the last Rolex chronographChronographA watch function for starting, stopping and resetting an elapsed-time measurement independently of the ordinary time display. with a smooth bezelBezelThe frame surrounding the crystal at the front of a watch. and the tachymeterTachymeterA chronograph scale that converts the time taken to travel a known distance into average speed. The distance and scale units must correspond. printed on the dial. Pump pushers and monochrome dials; made alongside the first Daytonas, hence the collector name.