DeutschTuning proudly offers DBA 4000 Series Drilled & Slotted Front Brake Rotor BMW 335d/335i E90/91 EACH. 4000 Series disc brake rotors are a direct replacement single piece brake rotor, designed for drivers seeking upgraded performance braking above and beyond standard OE levels.Cast from high carbon alloyed iron and undergoing Thermal Stability Profiling, DBA's metallurgy can handle the increased stress and heat generated under intense braking applications, time and time again.Featuring DBA's Kangaroo Paw ventilation that implements a series of 144 diamond and teardrop patterned pillars, DBA achieves up to a 30 increase in surface area and 20 improvement in cooling efficiency (as compared to a traditional straight vane design). Symmetrical slots and/or chamfered drill holes facilitate the exit of friction dust and gasses, for a quieter and more responsive pedal feel.Anti Rust: Painted non-friction areas to prevent rust and enhance appearance, or full En-shield coating to protect the rotor and alleviate the need for pre-installation cleaning. Bi-Directional Use: Symmetrical slotting and/or drilling for universal left/right use. Heat treatment cycles realign the microstructure of the iron, resulting in increased rotor stability and durability. Centre-split core castings for increased heat transfer and thermal efficiency. Paint markings change colour at specific temperature thresholds to assist with the monitoring of braking temperatures and rotor fatigue. CBN (Cubic Boron Nitride) machine turned finish, minimising disc thickness variation and the potential for pad "knock" and resulting premature wear.