Product Description: Advantages: 1.Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified,which include Part Number,Model Number and inspection date information 2.If you have any questions about the item,please provide us the Manufacturing Part Number for checking,your profits will be guaranteed.3.Made of aluminum and rubber, strong and durable, not easy to wear.4.The circumference is 200mm, the aperture is 6mm, it has high resolution and good use effect.5.It is used in conjunction with a rotary encoder to measure the conveying speed and position, which is convenient and quick to use. Specifications:Material: Aluminum + RubberColor: Black + SilverPerimeter: 20cm/7.87inchDiameter: 6.5cm/2.56inchBore Diameter: 0.6cm/0.24inchTotal Height: 1.7cm/0.67inchSize: 6.5x0.6cm/2.56x0.24inch(ODxID)Weight: 180g Package include:8 x Screw4 x Wrench4 x Encoder Wheel