Irwin Speedbor 12 x 1/4 in. Wood-Boring Spade Drill Bit Extension is designed to provide extra reach for your drilling needs. This extension features a double set screw with an Allen wrench for secure attachment, making it i for all 1/4" round shank drill bits. It is for use with bits that are 5/8" and larger, allowing them to follow through holes with ease. The 1/4" shank fits only round shank Speedbor or Do it brand bits, ensuring compatibility and performance. The extension measures 12 inches in length and comes packaged individually on a card for convenience. Model Number: 88601