Accompanied by a Rolex green leather presentation box and polishing cloth.
The present Explorer II model is from the very first series of the reference 16550, introduced into the market in 1985 replacing the reference 1655. It features the much sought after ivory dial, also called "rail dial". The name is derived from the warm ivory-color of the dial in conjunction with the symmetric division of the two lines below the center: "Superlative" and "Officially" to the left, clearly separated by a vertical space (thus "rail"), and "Chronometer" and "Certified" to the right.
The "ivory" or "rail" Explorer II models were produced in a very small series only and are considered highly collectable in today's market.
Various examples of the reference 16550 are illustrated in 100 Years of Rolex by F. & G. Mondani.