High-strength aluminum Works with any 2-3/8" Stowable table post (sold separately) Choice of four finishes: Anodized, Polished, Kennedy Gray, or Black Krinkle 7? diameter, with 5-3/4? hole mounting pattern Available as locking or non-locking 2-3/8? Tapered to 2-1/4? Requires a 3.5? Hole through deck Warranty: 5 Years