The first tanks were known as the Mark I after the subsequent designs were introduced. Mark Is that were armed with two 6 pounder guns and three .303 Hotchkiss machine guns were called "Male" tanks; those with four Vickers machine guns and one Hotchkiss were called "Female". To aid steering, a pair of large wheels were added behind the tank. These were not as effective as hoped and were subsequently dropped. Designer M Bergman