Milwaukee Twins Vented Rear Steel Disc Brake Rotor For Harley Softail / Dyna / Sportster The Milwaukee Twins Vented Rear Steel Disc Brake Rotor combines function with design, featuring a vented stainless steel build for improved cooling efficiency. It's crafted with a 420 steel plate that is induction hardened for exceptional durability and wear resistance. Precision engineering ensures it operates smoothly and accurately for reliable braking performance. Formerly offered under the J&P Cycles brand. Features: Vented stainless steel finish Surface induction hardened with a 420 steel plate for superior wear Precision ground for trueness Replaces OEM 41789-92