Utilizes Bluetooth« 4.1 to deliver incoming and outgoing audio for music, phone calls, GPS directions, and intercom conversations with a passenger or a riding companion up to 400 meters (0.25 miles) away The 2-button control for the 3S Plus Boom is incorporated directly into the boom mic, eliminating the need to affix any external elements to your helmet This Bluetooth headset allows up to eight hours of talk time on a single charge and seven days of standby time Charging the headset is easy thanks to the new USB-C connection Speaker drive unit: 23 mm - thickness 4.3 mm Boom Microphone: length 180 mm. SENA HEADSET 3S-PLUS B