Shimano's RT-MT800 compact and lightweight disc brake rotors feature rapid heat dissipation thanks to Ice Technologies Freeza heat management system. Installing and removing the rotors is quick and easy with Shimano's Center Lock design. Advanced heat sync design reduces brake fade. Technologies Freeza rotors Ice Technologies combined with Freeza disc brake rotor construction rapidly dissipates heat for more consistent braking performance in extreme conditions, longer pad life, and less brake fade and noise. Benefits FeaturesLightweight clad rotors with heat dissipating paint on exposed aluminum layer segments provide superior cooling, consistent brake performance, and lighter operation under all conditions. Clad brake pads with Aluminum/Stainless fins support rapid heat dissipation which helps reduce maintenance, provide longer pad life, and create less brake fade and noise. Shimano Center Lock The Center Lock system makes an easy rotor installation possible with spline mount and a lock ring. The lock ring mounting system reduces the total working hours by shortening the amount of time of both installation and de-installation. In addition, the secure fixing by the spline mount enhances precision and rigidity while improving braking efficiency. Fixing nut included.