Simplex is a French brand of bicycle components, founded by Lucien Juy in Dijon, who produced his first derailleur in 1928. It made a name for itself through its innovations in derailleurs, including the parallelogram design and the early use of plastic materials in the 1960s. Over time, Simplex equipped many French competition bicycles and was a highly respected name in the cycling industry. Towards the end of the 1980s and 1990s, Simplex experienced financial difficulties, its divisions were sold, and its production declined until it ceased.