Fox fork volume spacers allow riders to tune the air spring compression curve by adding these volume spacers. Features: Changing volume spacers internally adjusts the amount of mid stroke and bottom out resistance More spacers = less air volume, providing a more progressive spring curve NA are first generation negative air spring forks using the transfer rod to equalize the air pressure. NA2 is the second generation where the transfer rod is removed Specifications: Model: Fox Float 32 NA2 Spacer Volume: 8cc Quantity: 5-Pack