Without Twin Disc's products, there would be no "pull" in a tractor pull. The company makes heavy-duty transmission equipment for an array of off-highway vehicles. Its lineup includes hydraulic torque converters, power-shift transmissions, industrial clutches, and controls. Applications for Twin Disc's transmissions include construction and military vehicles. Manufacturers of rock crushers, hay grinders, and wood shredders use the company's clutches in their products. In addition, Twin Disc supplies marine transmissions and surface drives to the commercial, military, and pleasure-craft markets. It sells through both a direct sales force and a distributor network; two-thirds of its sales are made outside the US.