All sizes are displayed in their UK format. EU sizes may differ.\nMT Rider Sync Motorcycle Helmet Communication Intercom Bluetooth MT-B01\nThe MT Rider Sync MT-B01 Bluetooth Motorcycle Helmet Intercom is a new intercom developed by MT Helmets and Midland, with a range of over 1000m, that perfectly fits MT helmets equipped with UCS-type Bluetooth pre-installation.\nWith phone/GPS connectivity, noise cancellation, and the very best features of the latest generation Bluetooth systems, the MT-Rider Sync transforms the riding experience into a much safer and more enjoyable one by improving communication between riders.\nMT Rider Sync Motorcycle Helmet Communication Intercom Features:\n--Communication: rider-passenger intercom\n--Range: over 1000m (direct, obstacle-free communication)\n--Voice control: features voice command recognition\n--Noise cancellation: equipped with DSP noise cancellation technology\n--Audio: stereo music(A2DP) with 36mm speakers\n--Battery life: 8 hours of talk tim.