The Shimano Ultegra BR-RS811-R Chainstay Direct Mount Rear Brake Caliper is a bottom bracket mount calliper that offers an ideal balance of lightweight and stiffness, making it the perfect choice for both enthusiast and competitive riders.RS811 bottom bracket mount calliper offers an ideal balance of light weight and stiffness, making it the perfect choice for both enthusiast and competitive ridersLow profile aerodynamic direct mount Super SLR-EV Dual-Pivot design provides superior brake performance and light actionMust be used in conjunction with super SLR levers for correct leverage ratioEnhanced brake arch proportions give a quicker linear response and increased powerCan be used on frames with bottom bracket / Chainstay direct mountsLow profile outer cable stop position improves cable routing for reduced frictionCartridge brake shoes for easy replacementConvex washers on the brake shoes offer toe-in brake adjustment and easy alignmentLightweight aluminium construction, with an anodi