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: 396gMaterial: Aluminum AlloyFixed Type: ClampThread Size: M8Connection Diameter: 20mm to 20mm/0.79 inch to 0.79 inchTotal Length: 79.5mm/ 3.13 inchOutside Diameter : 55mm /2.17 inchPackage List:1x Flexible Shaft Coupler