The Hydra Flak Tank is the main mobile anti-air artillery piece of the Imperial Guard. It is produced on hundreds of Forge Worlds across the Imperium and is widely-used in nearly every regiment. The Hydra, like many other Imperial military vehicles, is based on the Chimera armoured personnel carrier chassis, and is armed with a Hydra Flak Cannon. The Hydra Flak Cannon consists of 2 Twin-linked Long Barrelled Autocannons mounted on a turret with sophisticated tracking and targeting equipment. The Hydra is used to defend important ground units such as Imperial Guard artillery batteries and armoured columns from enemy air attacks. Non-mobile units or structures are usually defended by a Hydra Platform, a stationary version of the Hydra Flak Cannon, while the Hydra itself is usually deployed with mobile units. The Hydra's powerful guns are capable of quickly reducing enemy aircraft to smoking debris, but they can also be levelled towards the ground to engage enemy infantry and lightly armoured vehicles when circumstances warrant. The Hydra's Autocannons are so effective in the destruction of enemy infantry that Imperial commanders often overlook this breach in regulations and some regiments will use their Hydras as front-line vehicles when the threat of air attack is reduced or no longer present. Hydra tanks are usually kept in their own company within a regiment, but are rarely deployed together in company formation and are instead assigned to other companies which require air defence.
The Hydra is armed with a turret-mounted Hydra Flak Cannon, which is composed of 2 Twin-linked Long Barrelled Autocannons that fire explosive flak rounds at an extremely high rate of fire. The Hydra's gunner and loader are positioned in the vehicle's turret and work together to keep the weapon's automated loading mechanism and complex targeting systems operational. The vehicle is also armed with a single hull-mounted Heavy Bolter, which can be used against enemy infantry that get too close. The tank can also be equipped with camouflage netting, extra armour plating, a Hunter-Killer Missile Launcher, a mine sweeper, improved communications equipments, a Pintle-mountedHeavy Stubber or Storm Bolter, rough terrain modifications, a searchlight, track guards, and smoke launchers.
28th Valhallan Armoured Regiment - The 28th Valhallan Armoured Regiment was stationed on the planet Betalis IV.
6th Cadian Armoured Regiment - The 6th Cadian Armoured Regiment made extensive usage of the Hydra during the defence of the planet Betalis III against the Eldar of Craftworld Mymeara.
2nd Brimlock Regiment, The"Sky Wardens" - The 2nd Brimlock Regiment depended upon the Hydra during the defence of Bastion 312 against rebel drop forces, and acquired a confirmed kill ratio of 99,999 to 1.
8th Valhallan Armoured Regiment - The 8th Valhallan Armoured Regiment made use of the Hydra during the Sallan's World Offensive.