Single Track. Portable behind-the-head wearing design, convenient for sports. Allow you answer or reject phone calls anytime and anywhere. Built in Microphone for Hands free Cell Phone use or chatting on QQ, MSN. Built-in lithium battery (charged via USB. Specifications: Bluetoooth

Single Track. Portable behind-the-head wearing design, convenient for sports. Allow you answer or reject phone calls anytime and anywhere. Built in Microphone for Hands free Cell Phone use or chatting on QQ, MSN. Built-in lithium battery (charged via USB. Specifications: Bluetoooth version:Version 2.1 Frequency: 2.4 - 2.48GHz Support format: MP3 WMA Talk time: Up to 4 Hours Charge time: 2 hours Power source: Built-in Li-ion Battery USB Charging) System requirement: Windows 98 or above Material: PC Item color:Blue Item size: 15 * 13cm/ 5.9 * 5.1in Item weight: 33g/ 1.2oz Package size: 19.5 * 16.5 * 7cm/ 7.7 * 6.5 * 2.8in Package weight: 85g/ 3oz