Centric 125 Series High Carbon Alloy Brake Rotors contain an advanced metallurgy that greatly reduces the possibility of pad squeal especially with higher friction, European style brake pad compounds. Proprietary Molybdenum and Chromium alloys resist rotor cracking during high performance use or repeat stop situations. This alloy also increases the friction couple improving brake performance and stopping power. Increased Chromium and Carbon content is also more resistant to oxidation. Centric Premium Rotor with advanced metallurgy that greatly reduces pad squeal; Especially effective with higher friction, European style brake pad compounds; Added Molybdenum and Chromium to resist rotor cracking 2008 - 2011 Audi S5, 2010 - 2012 Audi S4