There were at least three models used for military purposes: The Holt 75, the Holt 120 and to a lesser extent the Holt 60. The Holt 75 was first produced in 1913. It used two tracks for steering. It had a maximum speed of 15 miles per hour (24 km/h) and had a gasoline engine. In addition to US production, 442 Holt 75s were built in Britain by Ruston & Hornsby in Lincoln. Production of the Holt 75 was to continue post-war until 1924.
