Turbo Groove automotive brake discs have a widened, arcuate slit that increases the flow of cool air, lowering the temperature of the brake pads and disc, while draining dust, dirt and hot gases better than a straight line, which can rust and become ineffective. Drilled holes remove surface gases when braking from high speed, while not weakening the structure of the disc as in through drilling. TECHNICAL DATA Type: Drilled and Slotted Full / Ventilated: Ventilated Number of holes: 5 Diameter (mm): 294 Height (mm): 75 Thickness (mm): 19 Minimum thickness (mm): 18 Axle application: Back APPLICATION Brand Model Engine Value Power (KM) Yearbook BMW Z4 E85 2.5 218 2006-2009 BMW Z4 E85 3.0 231 2003-2006 BMW Z4 E86 3.0 SI 265 2006-2008 BMW Z4 E85 3.0 SI 265 2006-2009 BMW (ALPINA) ROADSTER S (E85) 3.3 2004-2005