This product is suitable for retrofit folding bike,city bike,electric bike.lightweight,high axial strength and compaility.Standard precision machining,chain retention,increases service life,and reduces friction.A good replacement for bike repair and upgradation,compale with many bike models.170mm crank arm length without any overlap of crank arm and chain ring bolt.Specifications: 48TBED double cover x 170MM handle square hole,with 9/16inch pedal axle,chain cover,Introduction: Compale with 6/7 speed post change,installation recommendation: suitable for lithium battery/bicycle type lithium battery/bicycle etc.Colour: blackMaterial: aluminum alloyPackage Contents: 1 x Crank setOnly the above package content,other products are not included.Note: Light 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.