Jaeger-LeCoultre's Manufacture, located in the Jou Valley of the Jura Mountains in Switzerland, has refined its manufacturing skills in producing high-quality timepieces since 1833. By 1900, more than 350 calibres had been manufactured, of which 128 had chronograph functions and 99 had repeater functions. For more than 30 years since 1902, it has provided a number of high-precision movements for Patek Philippe. In 1907, the world's thinnest pocket watch was successfully developed. In 1929, the caliber 101, consisting of 74 parts, weighed only 1 gram and created the world's smallest hand-wound caliber. In 1931, the reverso of the reversing case was a major break, and in 1968 Hollaris was equipped with a patented system that optimized sound transmission underwater. In 2013, a new type of timepiece without a gyro tourbillon bridge was announced. Since its inception, more than 1200 calibres have been created and continue to evolve a variety of lineups, pushing the top level of the watch industry.