TANK, MARK XA development inspired by the rhomboid tanks fielded during the Great War seven years prior, the first entry in Sevvania's domestic tank production was initially designated with an X to denote its experimental status but retroactively became known as the "Mark Ten" due to an R&D miscommunication. Two variations were produced: an anti-infantry model armed exclusively with machine guns, and an anti-tank model with a 57mm gun mounted in a sponson in the forward superstructure. Both vehicles also incorporated firing ports for rifles and handguns. Two in-line 6-cylinder engines were capable of propelling the vehicle approximately 10 miles per hour.
•In Service: 1925
•Crew: 4-8 (commander, driver, gunner, loader, mechanic, four additional machine gunners when in anti-infantry configuration)
•Armor: ~20mm
•Armament (AP configuration): Water-cooled .50 caliber machine gun, .30 caliber machine guns (x4, in sponsons), rifle ports (x2), rearward pistol port
•Armament (AT configuration): "Quick-firing" 57mm cannon, .30 caliber machine gun (in driver's ball mount), rifle ports (x2), rearward pistol port
•Speed: 10 mph
HEAVY TANK MARK XIEnvisioned as a breakthrough tank, the Mark XI was more heavily armored than its predecessor and featured both a turret-mounted gun-mortar and a secondary anti-tank cannon.
•In Service: 1935
•Crew: 5 (commander/gunner, loader, secondary gunner, driver, radio operator)
•Armor: 40-50mm?
•Armament: 50mm gun-mortar with coaxial 7.62mm MG, 30mm anti-tank gun, rearward SMG cupola (9mm)
•Speed: 20 mph