Muse M-276BT. Connectivity technology: Wired & Wireless, Bluetooth. Wearing style: Head-band, Headset type: Binaural. Ear coupling: Circumaural, Headphone frequency: 20 - 20000 Hz, Headphone sensitivity: 108 dB, Impedance: 32 ?, Driver unit: 4 cm, Magnet type: Neodymium. Foldable. Weight: 340 g. Product colour: Black