Centric Premium Rotors feature an Electrocoating (E-coating) finish that provides long lasting corrosion protection. Unlike phosphate finishes that provide only minimal protection from the elements, E-coating is a superior electrostatically applied finish designed to withstand 400 hours of salt water exposure without rusting. Centric Premium Rotors are double disc ground with a taper-free finish. Double disc grinding ensures parallelism, eliminates run out and provides near perfect disc thickness variation (DTV). Double disc grinding leaves a non-directional finish on the friction surface area for more effective pad-rotor break in.