The armoured bulldozer is a basic tool of combat engineering. These combat engineering vehicles combine the earth moving capabilities of the bulldozer with armour which protects the vehicle and its operator in or near combat. Most are civilian bulldozers modified by addition of vehicle armour/military equipment, but some are tanks stripped of armament and fitted with a dozer blade. Some tanks (called tankdozers) have bulldozer blades while retaining their armament, but this does not make them armoured bulldozers as such, because combat remains the primary role—earth moving is a secondary task.