Partial drawings have survived and show a vehicle long and about tall and three metres wide, not that much larger than the Mark I. However, the weight was estimated at roughly a hundred tons, much heavier than the 28 tons of the Mark I. The huge increase in weight came from the enormously thick armour for the time (three inches at the front, two inches on the sides). The hull roof consisted of a horizontal half-cylinder, apparently also with a uniform armour two inches thick. The front was a vertical half-cylinder, the transition between the two being a half-dome.