●Thickness: 2mm/0.08"; Inner Diameter: 35mm/1.38"; Outer Diameter: 42mm/1.65" ●Compatible with Bafang BBS01/BBS02/BBSHD mid-drive motor. ●Used where the engine housing interferes with the chainstays of the bicycle; Place one or more spacers on the motor shaft before inserting them through the bottom bracket housing, placing the motor unit further outside on the drive side of the bike ●Made of metal, rust-proof, corrosion-resistant, sturdy and durable. ●The spacer is lightweight and portable, does not strain your bike and makes riding time more enjoyable