SENA SF4 Bluetooth Communication SystemSENA SF4 Bluetooth Communication System SMALL GROUPS CONNECTIVITY & COMMUNICATION The SF4 is the perfect device for riding with friends by providing connectivity for small groups. The SF4's 4 way intercom has a range over 1. 2 kilometers (. 80 miles) so you can easily stay connected with your group in open terrain. The SF4 also uses smartphone connectivity, allowing for music streaming, taking and making phone calls, and hearing turn by turn GPS