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 [HEAVY] in their profile are known as Heavy weapons. Each time an attack is made with such a weapon, if the attacking model’s unit Remained Stationary this turn, add 1 to that attack’s Hit roll.