More Details:<br><br><br><br><br><br><br>Specification:Brand Name: ZHDAModel Number: ZD100<br> Horn Type: Bone Conduction Loudspeaker<br> Sensitivity: 123 + 5dB<br> Microphone: -42dB + 3dB<br> Frequency range: 20Hz-20000Hz<br> Battery: Lithium ion battery (360MAH)<br> Playing Time: 8 hours<br> Charging Time: &amp;lt; 3 hours<br> Effective Range: 10 m  Note:   Red flashes quickly: the electricity shortage   Long red light: charging   A long blue light: complete charging   Blue and red flashing alternately: pairing   Blue slow variable flash: Bluetooth Headset and paired mobile phone is not connected.  The reason is Headset or mobile phone not on， or the distance is more than 10 meters (30 feet).   Blue flash slowly: connected \/ is \/ are playing flash audio call.   Blue flashes quickly: receiving the call  Package Included: 1 X ZHDA Bone Bluetooth Earphone 1 X Charging Cable 1 X Earmuff 1 X Instruction