The Daytona is a chronograph built for measuring average speed over a known distance — hence the tachymetric scale on the bezel rather than a rotating one — and it is the reference on which Rolex's reputation in the auction room largely rests. Calibre 4131 is the current in-house chronograph movement, with a vertical clutch and Chronergy escapement. No date; water resistant to 100m. What matters on examination: chronograph function through start, stop and reset, with the hands returning precisely to zero; pusher feel, which is where a tired chronograph declares itself first; case sharpness; and on a gem-set execution, that the original papers specify the stone configuration and that the setting sits even across dial and bezel. Confirmed through the desk. Maker: Rolex. Reference: 126535TBR-0002. Available through ELITA's private desk — verification review, discreet handling and storage. Price on request.