Sneak Attack adds precision damage to qualifying attacks and can trigger effects from strike talents.
Sneak Attack damage dice apply only to attacks made with the character’s designated Primary Weapon. Off-hand attacks, secondary natural attacks, and automated bonus strikes such as Rend do not add Sneak Attack damage dice.
Secondary and off-hand attacks can still check whether the target is Flanked or Flat-Footed and apply strike-talent effects that trigger on a qualifying hit, provided the attack deals at least 1 damage after Damage Reduction. For example, Crippling Strike and Bleeding Strike can apply without adding Sneak Attack damage dice.