Stillen 2-piece sport rotors are the best choice for performance, durability and style when staying with oe factory calipers. these high-performance upgrades directly replace those plain oe factory rotors with no modification required. these track-developed rotors are mounted on aircraft aluminum hats, which are anodized to look great and stay that way. special hardware is used to handle the punishment of repeated thermal heat cycles. maximize your long-term investment by only needed to replace the outer iron rings when the time comes as the hat is reusable.