Irwin #4 Unibit Self-Starting Stairstep Bit, 12-Step, 3/16" to 7/8" Dia, 1/8" Depth: * Drill a range of holes without changing bits when you equip with a stairstep bit * SpeedPoint tip penetrates quickly and cleanly without the walking issues common among alternative point designs * Patented single-flute edge provides precise depth control though all size steps * Hex-shaped shank enables secure, slip-free lock down * Self-starting bit may be used on stainless steel, copper, brass, aluminum, plastic, laminates and wood * Material(s): Steel * Drill Bit Range (Min): 3/16" * Drill Bit Range (Max): 7/8"