The third CAS for the Liger Zero (in both the anime and models), the CP-21 Panzer is specifically designed to be a heavy-artillery Zoid. It has a great number of missiles, as well as two powerful "Hybrid Cannons", and is wrapped in a thick armor that offers much more protection than the basic armor. However, this comes at a cost, and the Zoid is not as agile as it would if it were to mount the other CAS units.
"Panzer" is German for "tank" or "armor".
In Korea, the Panzer CAS was released by Academy, and sold boxed along with the base Liger Zero. The Korean version of this Zoid was produced in limited numbers and is somewhat expensive and hard to come by.
A chromed version was released by TOMY in limited numbers.
Introduced in ZAC 2101, the Panzer proved to be the most effective of the Zero CAS units. The Zoid was employed against the swarms of Eisen Dragoon attack Zoids, using its missiles to decimate whole formations at once.
In New Century, the Liger Zero Panzer was the final, and the least used, of the three CAS units. This was because, despite having much more firepower than the other systems, it was so heavy that the Liger Zero was effectively immobilized by the weight (although in the Battle Story the Panzer was capable of moving at a respectable 285 km/h). Furthermore, it caused the Liger's systems to overload and generate excessive quantities of heat. This meant that it was a unit that could potentially inflict permanent damage to the Liger. It was eventually deployed against the Elephander in the Blitz Team's third encounter with the Zoid. It was not only able to effortlessly withstand the Elephander's AG unit's missile attacks, but it was also able to shatter the Energy Shield that had previously shattered the Schneider's blades. However, it did not actually defeat the Elephander, and shut down from the excessive strain that using the Panzer's weapons put on the Liger. It was only when the Backdraft showed up that the Zoid rebooted itself, unleashing a missile barrage (called the Burning Big Bang) that annihilated the Backdraft's unmanned Zabats. Apart from in minor roles, the next appearance of the Panzer would be against the Berserk Fury, as Bit had damaged the other two CAS units in prior episodes. It would be unable to penetrate the Fury's shield, but would help vaporize a falling Judge Satellite with its missile barrage (which Bit erroneously calls a Megabomb). As this missile barrage caused the Panzer to spontaneously overheat, it was ejected, and the basic armor was used for the remainder of the battle.
The Panzer appears in the New Century manga, where Bit uses it to fight against Altair and the Berserk Fury.