Napoer Wireless Bluetooth Headset Music Beanie Warm Knitted Hat Winter with Stereo Speaker Hands-free for Outdoor Running Camping One size fit all(16.92"-26.77") V3.0+EDR Bluetooth version,can pair with most of devices with Bluetooth function Built-in Li-ion chargeable battery, charge via USB Cable Handsfree speaker so that we can keep warm when have a phone call, voice chat and listen to the music in winter Built-in MIC,available for cell phone to transmit the speaking phone to your audio devices directly so that the user can hand free answering phone up via the device