Your ability to strike stealthily improves your magical strikes.
Benefit: Your levels in classes which grant the sneak attack ability count as increasing your caster level for purposes of determining the bonus you receive from the Arcane Strike feat. A class which both grants sneak attack and increases your caster level is not counted twice. (i.e., a Wizard 3/Rogue 3/Arcane Trickster 4 counts as caster level 10 for Arcane Strike.) In addition, during a round in which you have activated the Arcane Strike feat, your sneak attacks deal an extra +1d6 damage.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.