Royal Oak perpetual calendars have always been admired by collectors as it combines two important elements of the firm into one the iconic octagonal case with its legendary perpetual calendar mechanism. In 1996 the firm released the ref. 25800 series featuring a 33mm diameter case it was intended for Ladies users but released as a Mens mid-size timepiece. What is notably interesting is that the watch utilizes the cal. 2141/2806 which was specifically developed and implemented for this specific reference and also features a leap year indicator on the dial. Exceedingly rare and scarcely produced for only a few years and possibly the smallest self-winding perpetual calendar wristwatch ever produced by Audemars Piguet the present lot was the first Royal Oak perpetual calendar model was made in white gold while most examples of the reference were produced either in stainless steel or yellow gold.