Finger Blade (3.5e Equipment)
From D&D Wiki
Finger blades are small metal finger shaped points that can easily be slid over one's fingers and used to effectively make a swift slashing strike, making them favorable for assassination. Due to the nature of these weapons, they must almost always be custom made to fit the fingers snugly.
A character wielding finger blades cannot be disarmed of them.
The hand wielding finger blades is considered a free hand for the purpose of casting spells with somatic components.
The above statistics assumes a set of three finger blades. A single blade has a third of the cost and weight, and causes 1 point of damage.