Allstar Upper Control Arm Shim (Pack of 10) is an upper type that is . 500 inches thick and has a dual mount design for use with a 6 inch bolt spacing. The shim is slotted for a 1/2 inch bolt. These shims allow easy adjustment of the caster/camber during front end alignment. The one-piece dual mount shims are also available in various other thicknesses if needed (all are sold separately). It is backed by a 90-day limited factory and sold individually.