The result was called A6. In March 1927 a wooden mock-up was presented and after approval a second and prototype were ordered which had to incorporate the new hydraulically operated Wilson epicyclic steering gearbox, the predecessor of the Merrit-Brown gearbox. By June 1928, A6E1 and A6E2 were presented to the Mechanized Warfare Experimental Establishment for trials. Vickers was on this occasion ordered to add armour skirts but keep within the weight limit even if it meant removing armour elsewhere; A6E3 had also been ordered.