The Flame Tank is exactly what it sounds like - a main battle tank equipped with a flamethrower. As an armoured unit, this tank can take a beating and still push onward, and its front-mounted flamethrower deals massive damage to unarmoured units. Additionally, it will ignore the defensive bonus provided by fortifications, so the Flame Tank is perfect for breaking your opponent's defensive line.
At this time, the Flame Tank is only available as a reward for completing reward tiers of the Operations system, and cannot be researched or produced like other units.