Irwin Tools 341008 8-Piece Professional Spade Drill Bit Set, Includes 6-inch Length Bits With 3/8-inch, 1/2-inch, 5/8-inch, 3/4-inch, 7/8-inch, 1-inch, 1-1/8-inch & 1-1/2-inch Bits. All bits have a 1/4-inch hex shank that fits all drills & 1/4-inch quick change adapters. Micro groove cutting edge & spurs produce a smoother hole finish. Double spur design scribes the hole nefore the chips are made; producing a cleaner hole & reducing vibration. Rugged storage case with rubber over mold for added impact resistance. Sliding latch design provides added security.