Twinwall® construction consists of two aluminum alloy tubes, one within the other Outer tube is 7010-T73, which has extreme resistance to mechanical damage and is anodized to prevent corrosion Inner tube is ultra high strength 7010-T6 aluminum and is hard anodized to resist wear from twist grip and controls Rubber seals are used to cover the ends of the outer tube to keep water and cleaning fluids out Laser marked in the middle for accurate positioning Each handlebar includes an updated injection molded foam bar pad for better protection and greater durability Requires model-specific 1-1/8" bar mounts for bikes originally equipped with 7/8" bars