Deadly (3.5e Equipment)
From D&D Wiki
Deadly: A deadly weapon allows the damage of sneak attacks to multiply on a critical hit. The critical threat range and multiplier are the same as the enhanced weapon. This property can only be applied to weapons rogues are originally proficient with. Bow, crossbows and slings so crafted bestow the deadly power upon their ammunition.
Moderate transmutation;CL 10; Craft Magic Arms and Armor, creator must be able to perform a sneak attack; Market Price: +3 bonus.