For riders looking to communicate with their passenger, the SF2 provides simple Rider to Passenger 2-way intercom communication up to 800 m (880 yards) in open terrain. For those who ride in small groups, the SF4 is equipped with 4 way intercom over 1.2 kilometers (0.8 miles). Both models let riders enjoy smartphone connectivity. Riders can listen to music and use the intercom simultaneously using the Audio Overlay feature. Please note that Audio Overlay works best with Android devices, while iOS offers limited functionality.