Rounded radius for added strength ACDELCO 18A1809A Disc Brake Rotor - 5 Lug Holes, Cast Iron, Non-Coated, Plain, Vented, Rear ; MSRP · $73.37 ; Get it by Monday, Mar 2 ; No Hassle Return Policy... ACDelco Advantage Disc Brake Rotors provide reliable vehicle braking power. Rr Disc Brake Rotor ACDelco Advantage 18A1809A OE Style Brake Rotor ACDelco 18A1809A Disc Brake Rotor Cross Reference Rear Disc Brake Rotor Quality validated for proper metallurgy and correct brake plate thickness ACDelco Non-Coated Disc Brake Rotor - Rear 18A1809A - The Home Depot They also feature a non-directional ground finish that minimizes thickness variation and helps to extend brake pad life. Application-specific vane configuration offers greater safety and performance, dampens noise and vibration, and maximizes airflow to keep your rotor running cool.