One of the five mobile suits developed as part of the Earth Alliance's G Project, the Buster is an artillery mobile suit and adopts the X100-series frame, similar to the one used by the Duel. It has firepower rivalling that of a battleship's, and is meant to provide rear support for the other units and to attack enemy ships or facilities from a distance. As such, its armament consists mainly of powerful ranged weapons, including a gun launcher, a high-energy rifle and two missile pods. The gun launcher and the high energy rifle are power intensive weapons, and as such they are equipped with their own sub-generators.
Both of them are also capable of combining to form weapons with higher output which is seemingly caused by the linkage of the sub-generators, what weapon is formed depends on the combination configuration. Although the suit has no close combat weapon, the missile pods can be used to discourage enemy units from closing in. Due to its role, the main sensor camera on Buster's head is very important and is protected with additional armor. The suit also has the new Phase Shift armor like the other units in the project, making it nearly impervious to shell firing weapons. [Source: wikia]
You can download this papercraft model here: