Three more contenders appeared in 1982: the Bismarck, the Cheetah Mk1, and the Cheetah Mk2. These prototypes were designed with technical assistance from a West German engineering firm, Thyssen-Henschel. The Bismarck was an eight-wheeled vehicle which weighed over forty metric tonnes and carried a 105mm Denel GT-7 tank gun. The Cheetah Mk1 was six-wheeled and carried a lightweight 76mm gun or a 60mm breech-loading mortar (adopted from the Eland-60); it resembled a modified TH-400. Also known as "Model 2B", the Cheetah Mk2 was eight-wheeled and possessed an inferior range to the Cheetah Mk1, but was considerably faster. These prototypes were trialled in March 1984 and the Cheetah Mk2 was accepted by the South African Army. The Armoured Corps had hoped to simplify logistics by replacing both the Eland and Ratel simultaneously with a new chassis that could double as both a reconnaissance vehicle and an infantry fighting vehicle, similar to the Ratel-90 interim measure, but these plans were shelved. A fourth, multirole eight-wheeled prototype evaluated in 1984 was rejected and a decision was made to retain the Ratel for the foreseeable future while pursuing the separate development of the Cheetah Mk2, now denoted as the "Rooikat". In its final form the Rooikat incorporated several features adopted directly from the Eland-90, namely the same auxiliary turret sights and the mounting of all eight wheels on trailing arms, with the same hydropneumatic shock absorbers and coil springs.