Reference 5050, Patek Philippe's first perpetual calendar wristwatch featuring a retrograde date made in series, was introduced at the Basel Fair in 1993, cased in yellow gold only. As of 1995, it was also available in pink gold, white gold and platinum but still exclusively with the silvered dial, applied Roman numerals, aperture for the moon phases, the very first examples with outer railway minute divisions. Following substantial demand from clients, Patek Philippe introduced a second version featuring applied baton indexes, a modified moon phases display now in form of a circular subsidiary dial, outer beady minute divisions and the addition of the designation "Automatic". It was discontinued in 2002.