The R1 Concepts drilled-and-slotted black brake rotor for 2008–2019 Ford E-350 Super Duty, rear right, is the axle-specific replacement described in the source. The product listing notes a drilled and slotted braking surface with a black finish, intended to serve as the rear-right rotor for E-350 Super Duty applications within the stated model years.
R1 08-19 Ford E-350 Super Duty Rear Right Drilled & Slotted Black Brake Rotor