Twin Disc, Inc. designs, manufactures and distributes power transmission equipment for a wide range of applications, including marine, off-road vehicle and industrial. The company was founded in 1918 to manufacture clutches for farm tractors.^[2] It is now a worldwide company with subsidiaries or sales offices in Asia, Europe, North America, Oceania, and South America.

Twin Disc torque converters (formerly made under licence in the United Kingdom which became their only European Division known as the British Twin Disc Company Limited of Stroud in Rochester Kent who specialized in agricultural tractors, forestry skidders and forklift trucks. Later production moved to Rolls-Royce) these were fitted to the British Rail Class 125^[3] diesel multiple units and some export diesel locomotives, e.g. NZR TR class.