When you work on an installation (pipe, tubing pass-through, custom lockset etc) that requires neat and precisely drilled large-diameter holes, these bits are a life saver. The HSS drills will cut through construction lumber, dense plywood, hardwoods, even laminate-covered particleboard. The design brilliantly compensates for the high torque loads on the larger drills with a unique double through-pin design. This minimizes the possibility of the bit getting stuck on the mandrel. Side slots clear debris and prevent binding. This is a real problem solver.