Two cutter spline bits have a series of 12 spline that slide into an equal but opposite set of spline in the drive system of the spline drive hammer. This positive engagement of spline to spline allows maximum transmission of energy from the hammer to the bit. Superior quality Carbide nibs are vacuum brazed to a heat treated steel body resulting in two cutting edges which pulverize the concrete as the bit turns and pounds the work surface. Available from 3/8 in. to 1-1/2 in. diameters as well as metric diameters. One per package.