The A9 was also known as the Cruiser Mk I and was designed as a light, mobile tank to bypass enemy lines and engage enemy communication lines. It was armed with a 2 pounder and a coaxial Vickers machine gun as well as two smaller turrets on either side of the driver's compartment housing another machine gun each. The later Mk I A9 CS (Close Support) was fitted with a 3.7" (94mm) L15 Howitzer which only fired smoke rounds.