- Bluetooth V4.1 - Portable lightweight and sweatproof design - Be compatible for : all cell phones , tablet pc. and other bluetooth devices. - Built-in microphone - Built-in rechargeable Li-ion battery - support connect 2 bluetooth device in the same time. - Support voice prompt in English - Support voice calls prompt, reporting calls number in English - Support power display - Support stereo listen music - Built-in 14.2mm nedymium driver - Clear bass resonance, CVC wind noise reduction, and superior sound isolation