This double roller high performance timing chain kit is a perfect complement to your high performance valve springs and other LS- Gen III/IV engine components. It offers greatly enhanced strength and accuracy compared with the stock piece and even allows for timing adjustments (advance or retard) of up to 8 degrees. The set contains an adjustable nine keyway billet steel crankshaft sprocket with a Torrington thrust bearing, two oil-pump spacer plates, and detailed instructions.