The model C of the GrFrn M-4. Their is only one in existance, due to the price of building the cannon. The cannon is a EXTREME prototype of multiple weapon types. Three weapons were used: the Thumper cannon, a Advanced beam cutter, and lastly, ECHO. The ECHO has been modified into a new version, or strain, so it is far more devestating. The tank uses two different strains, strain 2, and 4. Strain 4 is a "odd" strain. This version can open a portal to a pre-determined position that is chosen during the creation of the strain. The second strain is the one that causes the damage, this one is a pulse - incendiary type explosive. First a EMP wave is emitted on impact, then a wall of fire closely follows. the Tank is kept on the Home carrier, several thousand miles away from the island, but still in firing range of the island.