The reference 6238 in 18k yellow gold was made in approximately 150 pieces, which makes it one of the rarest chronograph produced. Reference 6238 has a first series hand for the constant seconds. Reference 6238 in yellow gold are always equipped with 72B numbered movement despite the fact that it isn't a certified Chronometer watch. Inside the caseback the Rolex signatures are engraved while other markings as well as on the bracelet are punched. One of the main reason why yellow gold chronometers have been produced in less pieces than steel ones is that yellow gold is more precious but softer and less resistant to scratches and damages.