IRWIN 10502ZR Unibit Step Drill Bit Set, 3-Piece This product is easy to use. This product is highly durable This product is manufactured in United States. 3 most popular Unibit sizes cover a wide range of applications SpeedPoint tip prevents "walking," gets fast starts, and eliminates the need for pilot/starting hole Single-flute cutting edge drills true, round holes with smooth, clean finish Hex shank provides secure grip in the drill chuck Recommended for sheet metal, metal plates, aluminum, fiberglass, plastics, plexiglass, and wood