Height: 15″ Anodized aluminum. Diameter 2-3/8″. Latch safely secures posts to base. Heights are from the top of the swivel to the deck (when the post is installed). Swivel seat mount adds 3/4″ to pedestal height. Use with locking Trac-LockT swivel seat mount (Sold Separately). Use with any Plug-InT base (Sold Separately). ABYC Class: (AD) H-31 Driver.