Description Integrated large chainring: To use the integrated type, you must use the three-crank chainring to remove the small chainring and use it. Long-distance riding: It can easily cope with flat roads and climbing with the standard road bike gear ratio for long-distance activities. Foldability: After installing the double chainring, the small round bar on the small lower tube to prevent the chain from falling should be removed. Because after installing the front derailleur, the chain will be fixed by the front derailleur. So the problem of chain falling will not happen again. Colour:Black Material:Aluminum Alloy Package Contents: 1 x Bicycle Conversion Seat 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.