Dura-Ace moves to the next generation. Tested in competition and taken to victory by pro riders in all conditions, including the 2012 Tour de France Team Sky. Cutting edge technology for the ultimate in control and confidence. Long, fast descents demand confidence – Dura-Ace brakes deliver. Keep your brakes sharp with these replacement brake block inserts. Key Features: R554C4 compound offers excellent performance in wet and dry. Designed to work with Alloy Rims. Official Shimano replacement brake blocks. Fit Dura-Ace R55C4 brake cartridges for BR-9000 and BR-9010 brakes. Supplied as a pair (to fit one brake).