From 2006, to get around FIA technical regulations that "all wheels must be made from an homogeneous metallic material", a carbon fiber variant found its way into Formula One when it was used by Scuderia Ferrari whom BBS supply its wheels to. At the Turkish Grand Prix, the rear shrouds were also adopted by Toyota and Toro Rosso and thus their use became widespread for all teams. Prior to being banned from the 1994 PPG Indy Car World Series, wheel shrouds were popular on superspeedways until Team Penske revealed that those covers could reduce drag by 2.5%.