the highest industry standard of watch manufacturing and thus abandoning the Geneva Seal. In December 2018, World Wide Fund for Nature (WWF) released a report assigning environmental ratings for 15 major watch manufacturers and jewelers in Switzerland. Patek Philippe was given the lowest environmental rating as "Latecomers/Non-transparent", suggesting the manufacturer has taken few actions addressing the impact of its manufacturing activities on the environment and climate change. Notable inventions and patents Patek Philippe has invented over 20 basic calibres and has received over 100 patents. The following are some of the important contributions from Patek Philippe to the watchmaking industry. In 1845, patented keyless winding and hand-setting system, which received a bronze medal at the 1844 Industrial Exposition in Paris. In 1868, created the first Swiss wristwatch. In 1881, patented its precision regulator. In 1889, patented perpetual calendar mechanism for pocket watches. In 1902, patented double chronograph. In 1916, produced the world's first lady’s wristwatch with complication (No. 174 603, a five-minute repeater). In 1923, launched the world's first split-second chronograph wristwatch (No. 124 8244). In 1925, created the world's first perpetual calendar wristwatch (No. 97 975), with a compact movement for pendant watches created in 1898. In 1933, created the Henry Graves Supercomplication, the most complicated mechanical watch in the world (24 complications) until 1989. In 1949, patented the Gyromax balance. In 1956, created the world's first all-electronic clock which, in 1958, received the "Award for Miniaturization” in New York. In 1962, a tourbillon movement achieves the world's still-unbeaten timekeeping precision record for mechanical watches at Geneva Observatory. In 1986, patented the secular perpetual calendar with retrograde date indication. In 1989, created the Calibre 89, the most complicated mechanical watch in the world (33 complications) until 2015. In 1996, patented annual calendar mechanism and introduced the first annual calendar model Ref. 5035. In 2003/05, launched the annual calendar Ref. 5250, being the world's first watch with silicon-based (the Silinvar alloy) escapement wheel. In 2006, introduced the silicon-based Spiromax balance spring. In 2008, introduced the Pulsomax silicon-based escapement. In 2011, introduced the Oscillomax ensemble, combining the Spiromax balance spring, the Pulsomax escapement, and the GyromaxSi balance. In 2014, created the Grandmaster Chime Ref. 5175, one of the world's most complicated wristwatches (20 complications). Notable models Most expensive pieces On November 28, 2012, the Patek Philippe Star Calibre 2000 Ref. 990/1 was sold at Christie's in Hong Kong for a final