The Tri Bolt attachment is unlocked at Level 6, and is available exclusively to the Crossbow in Call of Duty: Black Ops II. It gives the Crossbow the ability to fire all 3 bolts at a time without needing to pull the bolt. The hit damage from all three bolts combined is enough to kill an enemy in core modes; however, the bolts move outwards horizontally, so this is only possible at close range. Unfortunately, this attachment forces the player to burn through already scarce ammunition and reload each time after the trigger is pulled. Scavenger can partially mitigate this problem, although it should be kept in mind that the Crossbow's reserve ammunition is limited to only one spare magazine. In addition, enemies killed by explosives (including the bolt's detonation) will not drop ammo packs. Enemies killed by other weapons or by the impact of the bolt, however, will drop ammo packs.
The Tri Bolt attachment is available exclusively to the NX ShadowClaw added via the February 8th, 2016 update. It remains the same as the version in Black Ops II except that the weapon can be fired twice in one magazine due to it having six bolts instead of three.