Wilwood GT36 Curved Vane Brake Rotor LEFTWilwood's GT 36 Curved Vane Spec 37 rotors are manufactured from a proprietary iron alloy developed to withstand extreme temperatures with the highest possible degree of resistance against distortion, warping, cracking, and wear. The formulation for this alloy is a derivative of technology and materials that were significant in the development of the extreme duty military spec rotors that are manufactured by Wilwood. Combined with our proven GT Series