1. The Main Body Is Expandable And Compatible With a Of Frame Types. 2. Lengthening The Built-In Telescopic Rod Can Improve The Stability Of The Bike Center Of Gravity When Pushing, And It Is Not Easy To Tilt. 3. Heightened Design, Don't Worry About The Small Diameter Of The Easy Wheel Causing The To Scrape The Ground. 4. It is made of aluminum alloy material and processed by CNC technology. The product is and has improved strength. Hollow design, exquisite workmanship, anodized Colour:Black Material:Aluminum alloy Size:Expanded size 138x50.5.x22MM Package Contents: 1 x Easy Wheels Extension Bar 2 x screw 4 x gasket 2 x wrench 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.