IRWIN 3041002 Speedbor MAX 5/8 in. x 6 in. Standard Length Tri-Plute Auger Speed Bit is the Fastest Speedbor spade bit ever and features Tri-Flute design for faster chip ejection. Cutting spurs have 3 cutting edges for added durability. Full screw tip allows the bit to self-feed. Grooved hex shank prevents slipping in drill chuck or bit extension. It fits all standard 1/4" quick change chucks.