a fob for a key chain , lanyard , or the like , supports a razor blade , or other knife blade suitable for cutting through relatively thin articles . the razor blade is embedded within the interior of a substantially rectangular - shaped molded plastic housing or casing defining the fob casing . the fob casing includes a slot intercepting one short side and the razor blade embedded inside the fob casing is positioned so that its sharpened blade edge intercepts the slot at an angle a distance from the mouth or opening of the slot . a suitable opening is included in the fob casing to support a key ring , lanyard , or other supporting axillary device .