Brazing formula optimizes drilling for up to 20% longer lifeUnique flute geometry provides efficient dust removalCentering point and 4-cutter design provide accurate and precise round holesFour cutter bits have a series of 13 spline that slide into an equal but opposite set of spline in the drive system of the spline drive hammerThis positive engagement of spline to spline allows maximum transmission of energy from the hammer to the bitSuperior quality carbide nibs are vacuum brazed to a heat treated steel body resulting in four cutting edges which pulverize the concrete as the bit turns and pounds the work surface