Each time a friendly operative fights in combat or makes a shooting attack with this weapon, in the Roll Attack Dice step of that combat or shooting attack, your attack dice results of equal to or greater than x that are successful hits are critical hits. x is the number after the weapon's Lethal, e.g. Lethal 5+.
Select a shuriken catapult the operative is equipped with (note that you cannot select a twin shuriken catapult). That weapon gains the Lethal 5+ special rule for the battle.