The diameter of the tube is 12mm,Suitable for smartphones, Motorcycles navigation systems, etc. , not easy to fade and not rust. The appearance of the fashion design, excellent technology is more suitable for your bike. Products can be installed and use without modification, easy to install, no installation instructions. Fitment:For X-MAX 300 2023- Note:Please confirm when placing your order that this product is suitable for your motorcycle. Colour:Black & Silver Material:Metal Size:12MM Package Contents: 1 * Navigation Bracket 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.