Twin heavy bolter

Weapons with [SUSTAINED HITS X] in their profile are known as Sustained Hits weapons. Each time an attack is made with such a weapon, if a Critical Hit is rolled, that attack scores a number of additional hits on the target as denoted by ‘x’

Weapons with [TWIN-LINKED] in their profile are known as Twin-linked weapons. Each time an attack is made with such a weapon, you can re-roll that attack’s Wound roll.