ULS Series Scalloped Rotors feature a fully machined scallop configuration that provides the highest degree of weight reduction on a vented straight vane iron rotor. Scallop machining will remove as much as three pounds, or nearly 33% of the rotor mass. The vented castings provide increased cooling capacity over machined steel plate rotors, with improved structural durability over drilled rotor designs. Wilwood's ULS scalloped iron rotors provides effective lightweight options for sprints, late models, modifieds, and other competition applications that race in low to medium temperature ranges. NOT for street use