Features1 Aluminium Alloy: The product is made of aluminum alloy, the hardness is much higher than that of the original steel sprocket, and it is sturdy and durable. 2Applicable: This sprocket spider adapter is compatible for Bafang electric bike mid drive motor BBS01 BBS02. 3High Accuracy: The product adopts aluminum alloy CNC cutting to ensure the accuracy of product use. 4Not Easy to Bend: The product has fine workmanship, which is not easy to be damaged and bent, and it has a long service life. 5High Efficiency: This product can make your motor spin faster and more efficiently, especially when you are riding on steep slopes.SpecificationItem Type: Sprocket Spider AdapterGross Weight: 229g/8.1ozMaterial: Aluminium alloyBCD: 104mm/4.1inFits: 7,8,9,10,11 speedsPackage List1 x Sprocket Spider Adapter