Round aluminum Precision Slide vertical post for Trail Rider ( X and Y-Spec only) and Sport Riders (X-Spec only) Includes plastic sleeve and steel insert Length of post 30" For easy access to the rear cargo area on SUVs and mini-vans, the vertical post can be tilted forward. *Y Spec Sport Riders need part number SPR-AP4 *Z Spec Sport Riders need part number SPR-ZRP *Z Spec Trail Riders need part number TRR-ZRP If you're not sure what spec you have, please send a photo of your rack to [email protected]