The optional Akrapovi? Sound Kit enables owners of selected Akrapovi? car exhausts to control the sound of the system from the cockpit of their machine. Using Akrapovi? technology, drivers can easily switch between the quiet mode and a sportier sound. With the use of a receiver to drive the actuators that open or close the valves at the end of the exhaust system, drivers can use the Sound Remote Controller or the new smartphone app (for iOS and Android) to regulate the valves.Akrapovi? Sound Kit P-HF1194 is developed for use with Slip-On Line (Titanium) only. If upgrading the slip-on system with evolution link pipe, specially developed Akrapovi? Sound Kit is already included within the evolution link pipe set.With the use of the optional Akrapovi? Sound Kit, the ECE type approval is no longer valid.Pictures are symbolic.