104bcd conversion base adopts aluminum alloy CNC cutting to the accuracy of product use. 104bcd conversion base is perfectly compatible with Electric bicycle Mid Drive Motor, 36V/48V 250W 350W 450W 500W 750W motor 104bcd conversion base material is aluminum alloy material, hardness is much higher than the original steel chain wheel, strong and ! 104bcd 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 multiple , city commuting 104 BCD Spider for Mid Drive 4 Chain Ring Bolts Weight:104BCD Conversion Base 42g 34T chain wheel 47g Applicable modified mountain bike 26/27.5/29er 20 inch folding bike 700C road travel bike colour:black Material:Aluminum alloy size:Thickness:4mm Package Contents: 1 * adapter plate Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.