This is a Metalstorm: Aces cannon.
It has maxed-out damage, and the highest tracking stat for any Metalstorm: Aces cannon. It and the 30mm Avenger are tied for the lowest heat rate. It takes 8 hrs to build, and you can finish it instantly with 40 insignia. It is very expensive, at 2000 Credits per 1000 rounds, so it should only be used for difficult Ace missions. Or, if you rarely ever fire your cannons, you should buy this cannon. If you use cannons a lot, however, you should buy the TT-32 Thunderbolt.