Akrapovic Sound Kit - BMW / F85 / X5MP HF947 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. CALIFORNIA WARNING: Cancer and Reproductive Harm www.