Jam-free performance features a dual-flute design to provide greater speed and control. Optimized for cordless drills in high speed. Rapid Strike tip creates fast, accurate starts and generates less heat. Optimized geometry with black oxide coating to cut faster and produce less heat. Laser-engraved reference marks are visible while drilling. 3-flat Secure-Grip shanks reduce bit slippage in the chuck. Includes 1 each: #1 step drill bit 1/8" - 1/2" by 1/32", #2 step drill bit3/16" - 1/2" by 1/16", #4 step drill bit 3/16" - 7/8" by 1/16", carrying case.