Portable behind-the-head wearing design, convenient for sports.Allow you answer or reject phone calls anytime and anywhere.Built in Microphone for Handsfree Cell Phone use or chatting on QQ, MSN.Built-in lithium battery

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