Mainly used for servo motors, spindle, step motor and so on.Wear resistant ,high hardness and excellent response.Super elastic torque can absorb vibration, appropriate a large torque transmission. Specification:Color: Silver ToneNet Weight: 153gMaterial: Aluminum AlloyFixed Type: ClampThread Size: M6Connection Diameter: 10mm to 12mm/0.39 inch to 0.47 inchTotal Length: 55mm /2.17 inchOutside Diameter : 40mm/ 1.57 inch Package List:1x Flexible Shaft Coupler