 It is developed around the year 2000 by the fictional Bolo Division of General Motors.By the 300-tonne Mark III it has AI allowing limited independent action and is powered by "ionic" batteries able to support combat-level activity for up to ten years and enabling operation even when fully submerged.The AI increases until the incorporation of Psychotronic circuitry in the Mark XX leads to Bolos becoming self-aware and capable of fully independent operation.