Sena SF4 DUAL pack Motorcycle Bluetooth Communication SystemSena SF4 DUAL pack Motorcycle Bluetooth Communication System The SF4 offers 4 Way Intercom functionality and FM Radio. All SF models include brand new capabilities such as Audio Overlay, Quick Charging and microphone mute option features. The SF Series boast a sleek and low profile design that will fit on almost any helmet. SF4 Rider to Passenger or Small Group Communication For those who ride in small groups, the SF4 is equipped with 4 way intercom