4x Micro Drilling Chuck Clamp 0.3-4mm with Wrench 3.17mm Shaft Connecting RodOOTDTY Features:High precision screw and taper hole. Strong impact resistance. Compatible with hammer drill and other electric drill. Specifications:Color: As the picture Material: High Carbon SteelOuter Diameter: 21.5mmTaper: 2 Degrees 49 Minutes 24.7 SecondsWork with 0.3mm-4mm( 0.01" - 0.16"),Maximum Clamping: 4.2mm. Connection size: JT0 (inner hole is 6mm diameter)JT0 taper largest end diameter: 6.350mmJT0 taper smallest end diameter: 5.800mm3.17mm brass Mini motor electric shaft clamp drill chuck for 0.3mm-4mm drill bit. Drill clamp JT0 rod connection connect motor drill for 3.17mm motor shaft.3.17mm shaft coupling connector for brass motor. Close Mount with 3.17mm Motor Shaft Copper Wire Rod For 0.3 - 4mm JT0 Clamp Material: BrassFit Motor Shaft Diameter: 3.17mm. Quantity: 1 SetNote: No retail package. Transition: 1cm=10mm=0.39 inchPlease allow 0-1cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package Included:1pc x Drill Chuck1pc x Wrench/Wrench Shaft Connecting Rod 1pc x 3.17mm