Sinn Spezialuhren GmbH & Co. KG was founded in 1956 by Helmut Sinn. Mainly focused on pilot's watches and chronographs at first, many of which were offered through direct sales at low prices, Sinn later focused on dive watches as well. In September 1994, Helmut Sinn sold the company to the former IWC staff and engineer Lothar Schmidt.
Sinn is known for innovative watch case designs and materials as well as the SZ family of in-house movement modifications.