These are front and rear poly sway bar inserts, they are stiffer than the OEM rubber bushings for better performance by reducing body roll.
Front 34mm and Rear 18mm will fit the ZZP Sway Bars. 18mm applies to the old ZZP rear sway bar, new bar is 25mm.
Front 32mm and Rear 18mm will fit the GMPP Sway Bars.
Sold in pairs. Each Sway bar will require 1 pair.