All sizes are displayed in their UK format. EU sizes may differ.\nSena 5S-10 Motorcycle Helmet Bluetooth Intercom Communication System\nBorn from the legendary Sena SMH5, the Sena 5S motorcycle Bluetooth intercom system is the next generation of feature-rich and value-packed intercoms from Sena. With this easy-to-use and accessible unit you get high-definition in-helmet speakers, high-definition two-way intercom and an integrated LCD screen. All the features you need at an amazing value.\nThe 5S with Bluetooth\u00AE 5.1 keeps you connected to your riding companion or passenger with HD Sound quality, music sharing and audio equalizer profiles built right in. It also lets you answer phone calls hands-free and hear your GPS prompts. The 5S features a motorcycle helmet clamp kit and boom microphone. The jog dial makes for an intuitive user interface that is much easier to control while riding, which means you'll ride safer. Available individually or in a dual pack.\nSena 5S-10 Bluetooth .