The HAG-M, alternatively called the Heavy Artillery Gun or mortar tank, functioned as a mobile artillery platform on repulsorlift technology. It saw use with both the Trade Federation and, subsequently, the Confederacy of Independent Systems.
In contrast to its predecessor, the earlier Heavy Artillery Gun, which bore a superficial resemblance to the Multi-Troop Transports utilized by the Trade Federation, the HAG-M's aesthetic mirrored that of the Armored Assault Tank.
Positioned just above the "foot" on its frontal side were sizable orange photoreceptors. Furthermore, its chassis was more extended compared to the AAT. Its sole armament was a mortar cannon, spanning almost the vehicle's entire length. This cannon possessed the power to readily obliterate the Galactic Republic's RTTs and walkers.
The HAG was encased in robust armor, providing significant resistance to laser cannons. However, this came at the cost of reduced speed and maneuverability, rendering it susceptible to destruction by quicker and more agile Republic vehicles. During the Clone Wars, it fulfilled a role similar to a lighter version of the Republic's Self-Propelled Heavy Artillery units.
An enhanced iteration of the HAG-M, identified as the HHAG-M, also existed. This variant featured a larger "foot" and was equipped with two mortar cannons.
Both the HAG-M and the HHAG-M saw action during the Trade Federation's invasion of Naboo and throughout the Clone Wars. They were deployed in environments where other CIS artillery, like the IG-227 Hailfire-class droid tank, would have been exceptionally vulnerable. They proved crucial in neutralizing larger walkers, such as the All Terrain Tactical Enforcer, by engaging these heavily armored machines before they could retaliate. Nevertheless, they required support from anti-air units, as Republic aerial vehicles could easily take them out.