A perpetual calendar in a rose gold Officer's case with retrograde complication is nothing new for Patek Philippe, although the 5159R-001 is a huge jump up from versions that have gone before. The retrograde complication allows the date indicator to instantly flick back to the first of the month at midnight on the last day of the month over a 270 degree arc, no mean feat. The perpetual nature of the watch means that, assuming it is kept running, it will not require adjusting. The moon phase indicator is so precise that it only requires correction of 1 day every 122 years. The new 38mm case means the layout is less crowded and the movement can be viewed through the hinged dust cover to the rear.