Irwin® Speedbor® Wood boring Bit Extension, Manual Locking, 1/4 in Shank, 6 in Length, 1-1/16 in dia Body, High speed steel, For Use with: 1/4 in Wood Bit. Irwin® Speedbor® 88702 Manual Locking Wood boring Bit Extension, 1/4 in Shank, 6 in L, 1-1/16 in dia Body