Features a unique grooved post design that provides security against rotation in the base and seat mount. Safely stabilized once the post is securely engaged in the base. Stainless steel hardware, high-strength aluminum, and engineering-grade plastics used throughout. High-Strength Adjustable Aluminum Post. Includes 2-3/8" Trac-Lock™ Non-Locking Air-Ride Swivel. Fits Any 2-3/8" Plug-In™ Base (sold separately)