A. Bafang Ebike Electric BBS01 BBS02 Bicycle Mid Motor Spider Chain Ring Adapter 104BCD 130BCD for MTB Electric Bicycle B. Features: C. Conversion base adopts aluminum alloy CNC cutting to ensure the accuracy of product use. D. Conversion base is compatible with Bafang Electric bicycle Mid Drive Motor, 36V/48V 250W 350W 450W 500W 750W motor. E. Conversion base material is aluminum alloy material, hardness is higher than the original steel chain wheel, strong and durable. F. Conversion base can be used with many accessories for mountain bikes and can be combined with a variety of configuration options, suitable for XC AM DH multiple routes, city commuting. G. Specifications: H. A: 5 claws (130BCD) I. B: 4 claws (104BCD) J. Color: black K. Material: aluminum alloy L. Note: M. Transition: 1cm=10mm=0.39inch N. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. O. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! P. Package Includes: Q. 1 Conversion Base