The tank A13 E1 was rudimentary and too small for British use but the Nuffield suspension was most effective and this became the basis of the Cruiser Mk III (A13). Following testing of two Nuffield-built prototypes (A13E2 and A13E3), the A13 was ordered into production and 65 were manufactured by mid-1939. The Mk III weighed , had a crew of 4, a 340 hp engine which gave a top speed of and was armed with a 2-pounder (40 mm) gun and a machine gun. When it was introduced in 1937, the army still lacked a formal tank division. The trackless element of the Christie suspension was discarded as adding little value for the extra complexity. The Cruiser Mk IV (A13 Mk II) had heavier armour than the Mk III and production started in 1938.