69023 3-Jaw Mini Chuck secures drill bits that are too small for a regular chuck. Holding capacity of the Mini chuck is 1/4" down to 1/64" (.0156")
28215 3-Jaw Micro Chuck (sold separately) secures drill bits even smaller than Mini chuck Holding capacity of the Micro chuck is #61 (.039") to #97 (.0059")
Micro Drill Chuck also sold separately.