M9 Wolverine

The M9 Wolverine was a self propelled Surface to Air Missile system based on the Half track design. It excelled at taking down Banshees and the older Spirit transport craft seen often through Halo wars or Reach. It saw action on Arcadia where it provided Air defense for the Rhino tank/artillery platforms during the battle to break the Covenant energy dome which hid a large Covenant base and refueling hub. This was then destroyed by several MAC strikes from the Spirit of Fire.
The M9 Wolverine was equipped with a single XM511 Heavy Grenade Launcher for anti-personnel purposes and M260 MLRS. While strong against aircraft it was weak against infantry and other vehicles. Though Upgrades to the vehicle would add additional launchers for increased firepower and an ability to volley fire at enemy structures, it was better used for it's initial purpose. To help secure air superiority and protect key installations while remaining mobile enough to avoid enemy counter fires. 
With the M9 being similar to a half track that meant it could handle rougher terrain should they need to move to a better position without time to circumvent obstacles. Also being a half track meant it could still move relatively quickly without having to remain on a road or bridge which allows for greater access to routes of attack or escape.