ARC's composite levers flex where aluminum bends. The ARC levers are lighter and tricker without sacrificing function - plain and simple. ARC Composite Folding Levers: Aircraft and race cars have used composite materials for years and now ARC has incorporated this technology into their levers. The ARC composite levers have the same functioning features as the ARC aluminum levers. The difference between the aluminum model and the composite is that the composite will never break. Strong enough to do the job yet can be bent and straightened over 20 times without any diminished appearance or strength. Adjustable for hand size and move to prevent damage in a crash. The "knee" is made from billet aluminum. All of the hardware is top grade. Lifetime warranty.