StopTech Sport Rotors are also available with an optional cryogenic treatment. Although cryogenic treatment is invisible to the naked eye, many fleet customers are sold on its ability to extend the service life of the brake rotor. Deep cryogenic treatment is a one-time process that permanently improves the performance and wear characteristics of metal components, from brake rotors and engine parts to machine tools and gear sets. All new StopTech Sport Rotors may be ordered with cryogenic treatment for an additional fee. Symmetric vane, split-core castings for uniform heat distribution. Black E-Coat anti-corrosive coating protects much better than competitors spray paint. Double disc ground friction surface for optimal performance and service life This extra process provides better rotor balance and creates a cleaner; more finished looking component; In addition; Rotors are inspected for balance and mill-corrected to a tolerance of less than 2oz 2010 - 2017 BMW 535i GT, 2011 - 2013 BMW 535i, 2011 - 2015 BMW 740i, 2011 - 2015 BMW 740Li, 2011 - 2017 BMW 535i GT xDrive, 2011 - 2017 BMW 550i, 2011 - 2017 BMW 550i xDrive, 2012 - 2017 BMW 650i, 2012 - 2017 BMW 650i xDrive, 2013 - 2015 BMW 740Li xDrive, 2013 - 2015 BMW ActiveHybrid 7, 2013 - 2017 BMW 528i, 2013 - 2017 BMW 650i Gran Coupe, 2013 - 2017 BMW 650i xDrive Gran Coupe, 2015 - 2015 BMW 740Ld xDrive