Small device worn on two fingers, which releases a powerful burst of energy in the form of a cutting beam. The laser-like weapon can cauterize flesh and easily kill targets, and is commonly used by Za'tarc assassins -- innocent men and women who have been brainwashed by the Goa'uld. It is also the weapon of choice for some Goa'uld.
The ring-like weapon is designed to be covert, and is activated by pressing the center of the small device. A second press will cause the device to overload and explode, killing the wearer -- which za'tarcs are programmed to do should their mission fail. The resulting explosion is powerful enough that it does not even leave the victim's brain in a sufficient state for study of the za'tarc brainwashing technology.
Divide and Conquer - Martouf, believing he is in the presence of the President of the United States, reveals a za'tarc weapon in the hopes of killing him and ending the treaty between Earth and the Tok'ra.
Chimera - Osiris arms herself with a za'tarc weapon as a back-up plan, and uses it to try and escape Dr. Jackson's home when her transporter access is cut off.