Shimano's Polymer Coated Inner Brake Cable is the slickest around.
Developed for the Dura Ace 9000 and Ultegra 6800 component groups, this inner brake cable is made from stainless steel and then given a polymer coating. This combination reduces friction and improves brake feel.
The Polymer Coated Inner Brake Cable comes with a 1.6mm width, 2000mm length cable for a single brake, one cable end, and two sealed ferrules.
Note: Shimano ONLY approves these cables for use with 9000 and 6800 series plus newer brakes with stronger cable fixing bolts.