Notes: The 77518 is a midsize/unisex 31mm no-date Oyster Perpetual that comes in a 18K Yellow Gold case with a fluted 18K yellow gold bezel It is matched with a stainless steel/18K yellow gold 3-link bracelet. The dial is typically white or champagne and the hour marks are typically simple indices .

Mechanism: The 2235 is an update to their already accurate and reliable Cal. 2135. The calibre 2235 is a self-winding mechanical movement entirely developed and manufactured by Rolex. Like all Rolex Perpetual movements, the 2235 is a certified Swiss chronometer, a designation reserved for high-precision watches that have successfully passed the Swiss Official Chronometer Testing Institute (COSC) tests. Its architecture, in common with all Oyster watch movements, makes it singularly reliable. This movement features date and date quickset functions.

This mechanism does have hacking capability.

Family Notes: In 1926, Hans Wilsdorf introduced the Oyster watch which used a waterproof case, hence the name. He added "Perpetual" to the name when in 1933 he introduced a reliable automatic self-winding watch. Hence the name means "Waterproof, Self-Winding" in Rolex-speak and generally means the watch is water resistant to a depth of 100 meters.