Irwin 88702 6" Extension Bit.
Bit Extension.  Double set screw with Allen wrench. Recommended for all 1/4" round shank drill bits requiring extra reach. Follows 5/8" and larger bits through hole. 1/4" shank. Pouched. Only fits round shank Speedbor or Do it Best brand bits. Length: 6", Shank Size 1/4".