This is a set of three tri-angle bits (small, medium and large) manufactured by and designed to fit some Microtech knives with the triangle screws.
The bits and handle are steel. These will fit most any screwdriver with interchangeable standard 1/4" heads. The handle serves as the driver and the bit being used is held in place with a magnet while the two smaller bits fit neatly into the tool's handle.
These wrenches are sold only as tool to adjust your screws. Disassembly of your knife will void your warranty. We know some of you will be unable to resist though... If you find the screws are tight don't try to force them. Heat up the screw to loosen any loc-tite that is present.
This is an unofficial list of what fits what: