Stunning Sniper
Critical hits with ranged weapons stun targets until your next turn.
Prerequisite: Proficiency with a ranged weapon
You have mastered the use of ranged weapons to cripple your target from a distance. When you score a critical hit on a ranged attack roll, you can stun the target until the start of your next turn instead of doubling the damage.
Source and licence
From Tome of Heroes.
Licence: Open Game Content (OGL 1.0a).