Key Hole Cutter Bit
Large Diameter x Small Diameter x Cut Kerf x Carbide Height x Shank
2 flute, Carbide Tipped. Plunging the bit produces 3/8" or 1/2" hole and moving the router creates a T-slot which will accept the head of a screw or nail.
Used for hanging pictures, plaques, clocks, brackets, etc. flush to the wall without additional hardware.