Centric premium rotors utilize an Electrocoating finish that provides long lasting corrosion protection. E-coating is a superior electro-statically applied finish designed to withstand 400 hours of salt water exposure without rusting. Phosphate finishes utilized by other manufacturers provide only minimal protection from the elements; these finishes are generally only effective for the shipping and storage portion of a rotor's life. The addition of heat and moisture eliminates the effectiveness of phosphate finishes resulting in immediate corrosion once installed in the vehicle. 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 serviced life 2016 - 2018 Buick Envision, 2017 - 2019 Buick LaCrosse, 2018 - 2020 Buick Regal Sportback, 2018 - 2020 Buick Regal TourX, 2018 - 2019 Chevrolet Equinox, 2016 - 2020 Chevrolet Malibu, 2018 - 2020 GMC Terrain