The Shimano SM-RT66 SLX RT66 6-Bolt 160mm Disc Brake Rotor is "Rider Tuned" SLX Group for Trail Riders providing durable and responsive braking. This design is great as a replacement or an upgrade. Stainless steel construction resists corrosion, and the mud shedding design keeps your pads free from debris. Original Shimano parts guarantees that all components work perfectly for optimum performance and maximum safety and longevity.