For the SPEEDBOR® Wood Boring Drill Bit Extension, 1/4 in Shank, 6 in (L), the small end or shank that goes in the drill chuck (left side in picture) is 1/4" in diameter round with 3 flats for the drill chuck to grip. The other end, the right side, accepts drill bits with a 1/4" diameter round shank. It will follow 5/8" and larger drill bits through the hole. This extension is not made for quick change wood boring bits.
Answered on 4/25/2013 by Community Answer from None