Battlegroup Name: Heavy AA Gun
Turret Class: Open
Turret Type: Rotating
Crew: 7
Speed: Fixed Place
Weight: 2,445 lb. (1,111 kg)
Engine: N/A

 As the name implies, this weapon was used primarily to defend against air attacks. Anti-aircraft guns were pressed into anti-tank service once it was discovered that their high velocity projectiles could penetrate thick armor. The 90mm AA guns were used as stopgap protection to counter the threat from Tiger and Panther tanks.
You will rarely see these big guns in your arsenal, use them wisely. A well-placed 90mm AA gun can break up an entire armored column. While the 90mm gun can't fire quite as fast as traditional anti-tank guns, you should still be able to get the drop on most German tanks. Since you will not be able to place this unit in buildings, protect its flanks with structures and wooded areas.