The Rolex 16550 is a very desirable variation of the Explorer tool watch. Considered by many as a transitional model, the ref. 16550 was responsible for introducing the Explorer line to a larger 40mm case size, a higher-beat calibre 3085 self-winding movement, and a scratch-resistant sapphire crystal. It was also one of the first instances of an Explorer model to feature classic Mercedes hands as well as the triangular, round, and rectangular hour markers that are often found on many modern Rolex tool watches. The Explorer II is a spelunker’s watch at heart and also includes a fixed 24-hour bezel, a dedicated arrow hand on the dial, contrasting lume for an easy reading, and substantial waterproofness. The ref. 16550 is a cult favorite among many used Rolex collectors in-the-know and is an excellent choice for your next luxury watch investment.