This small Micro Drill Adaptor ( sensitive drill adaptor) is like a miniature quill & is designed to drill small holes using a lathe, mill or pillar drill Sensitive Finger Control. Controls manual feed pressure very easily. Helps in preventing Drill breakage and well suited for making small holes with large machines. Shank is 1/2" Inches (12.5 mm) Straight Parallel Drill Chuck Taper is JT0 (**Drill chuck is not included in this listing & costing). This small JT0 Drill chuck capacity is 0.4 to 4 mm See this video, which is not our property but we had taken just the reference to make our customers understand about it;