This product is suitable for retrofit folding bike, city bike, electric bike. lightweight, high axial strength and compatibility. Standard precision machining, chain retention, increases service life, and reduces friction. A good replacement for bike repair and upgradation, compatible with many bike models. 170mm crank arm length without any overlap of crank arm and chain ring . Specifications: 48TBED double cover x 170MM handle square hole, with 9 or 16inch pedal axle, chain cover, Introduction: Compatible with 6 or 7 speed post change, installation recommendation: suitable for trendy lithium battery or bicycle type lithium battery or bicycle etc. Colour: black Material: aluminum alloy Package Contents: 1 x Crank set Only 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.