To be used in combination with Carbide holesaws.3834-DRL-CT fits any arbor except for arbors with core ejector function.Carbide tipped pilot drill makes a hole in the work piece before the teeth of the holesaw become engaged, guiding and keeping the holesaw in correct position during the sawing operation.High grade carbide tip with special properties, hardness and geometry.Specially designed to provide one tool to cover many different materials