Mostly referred as ‘Pre Daytona’, the 6238 is the last Rolex chronograph with the tachometer scale printed on the outer track of the dial and smooth bezel. A fantastic design, extremely ahead of its time, is the last ref. produced before the 6239 Daytona, usually fitted with a silver dial. The Black Galvanic ones are a pinnacle of Rolex collecting. Generally acknowledged with serial number up to 1.6m, this watch is one of two known with serial 1.9 making it even more desirable.