Feature:1. Built in Lithium Re-chargealbe battery 3.7V/200 MA 2. 3.5mm Stereo Jack. 3. USB Cable for battery re-chargeable. 4. Twin colors LED indicator. (Red/Green) 5. Power On/Off Switch. 6. Low Power indicator. 7. Power Output: 2 W 8. Rubber Coating in product surface.