SRD:Sword of Subtlety

Sword of Subtlety: A +1 short sword with a thin, dull gray blade, this weapon provides a +4 bonus on its wielder’s attack and damage rolls when he is making a sneak attack with it.

Moderate illusion; CL 7th; Craft Magical Arms and Armor, blur; Price 22,310 gp; Cost 11,155 gp + 892 XP.