Wireless Bluetooth Headphone Earphone Headset Hand-free Mic for Phone & PC Color Black Compatible with most bluetooth enabled cellphones when used to answer or reject the phone calls but only compatible with Nokia devices when listen to music! Allow you answer or reject phone calls anytime and anywhere. Portable behind-the-head wearing design, convenient for sports. Built in Microphone for Handsfree Cell Phone use or chatting on QQ, MSN. Built-in lithium battery (charged via USB). Single Track. Compatible with most bluetooth enabled cellphones when used to answer or reject the phone calls but only compatible with Nokia devices when to listen to music!