Akrapovič - Akrapovič Sound Kit - BMW X5 M (F85) (2015-2018)This easy to use optional extra gives the driver the opportunity to switch between dual mode settings for either a sporty sound between the deeper and higher frequencies, or the more regular Akrapovi sound. It works by fully controlling the opening and closing of the exhaust valves simply by pushing a button on the Sound Remote Controller or via the downloadable app. Pictures are symbolic.