Flexibility of coupling shaft removes stress between the motor and driving components. The shaft couplers are widely applied to small CNC machines, encoders, and 3D printers for Z-axis coupling, simplifying the debugging process. 6mm to 8mm shaft diameter, 25mm length, 18mm outer diameter, set screw type, beam coupling. Zero backlash. One-piece metallic spring coupling. Designed for light torque shaft connections. Absorbs parallel, angular misalignments and shaft end-play through spring action. Widely used in drive systems for encoders, instrumentation, lead screws, small pumps, feed rollers, and other applications requiring light to medium duty, torsionally flexible couplings. Material: Aluminum alloy Color: Silver Weight: 70g Package Contents: 5 x Shaft coupling Only the above package content is included; other items are not part of this package. Note: Light reflection and different display settings may cause slight variations in the color of the item in the picture compared to the actual product. Measurement may vary by +/- 1-3cm.