Features:Type:Mini Electric Motor ShaftMaterial: BrassMatch the motor shaft Diameter:3.17mm3.17mm Brass Mini Electric Motor Shaft Clamp Drill Chuck for 0.3mm-4mm Drill.Drill Clamp JT0 Connection Rod Connect Motor Drill for 3.17mm Motor Shaft.3.17mm Shaft Coupling Motor Connector BRASS.Close-fitting with 3.17mm motor shaftCopper rodfor 0.3~4mm JT0 dirll clampStrong impact resistance.High precision screw thread and tapered hole.Compatible with impact dril and different power electric drill.Specification :Color:as picture showMaterial:High-carbon steelOuter diameter: 21.5mmTaper: 2 degrees 49 minutes 24.7 secondsWork with 0.3mm-4mm( 0.01" - 0.16") Drill,The maximum clamping: 4.2mm.Connection size: JT0 (inner hole diameter is 6 mm)JT0 taper the biggest end of diameter: 6.350mmJT0 taper The smallest end of diameter: 5.800mmNotice:Due to the different monitor and light effect,the actual color maybe a slight different from the picture color.Include: 1 x Drill Chuck1 x Spannerkey1 x 3.17mm Shaft Connecting Rod