Jaeger-LeCoultre
Founded by Antoine LeCoultre in the Vallée de Joux; has made hundreds of its own movements and supplied other brands. Known for the Reverso of 1931, with its reversible case, and the Atmos clock.
Antoine LeCoultre set up a workshop in Le Sentier in the Vallée de Joux and invented, among other things, a machine for measuring microns. In the 20th century the firm worked with the Paris chronometer maker Edmond Jaeger, and the name became Jaeger-LeCoultre in 1937.
The Reverso was meant to survive polo: the case can be turned over to protect the glass. The Atmos clock is driven by small changes in temperature and in principle runs without being wound. The brand is now part of Richemont.
The signature LeCoultre (in the US) or Jaeger-LeCoultre; calibre number on the movement.