The IWC Portugieser Perpetual Calendar 5021 was released back in 2003, showcasing the combination of IWC's self-winding 7-day movement and Kurt Klaus' brilliant perpetual calendar module. This module was first used in the 1985 Da Vinci and was modified to fit the larger size of the 7-day movement. With a 44.2mm case and sapphire glass on both sides, the watch boasted a unique 'Double Moon' display, allowing the wearer to track the moonphase in both the northern and southern hemispheres. In 2006, the slightly smaller 5022 ('Single Moon') was introduced alongside the 5021. The IW5021-20, also known as