Momoday Outdoor Bluetooth Beanie -Washable Wireless Bluetooth Hat Headphones Headset Earphone with Built-In Stereo Speakers & Mic (Gray) Knitted material, fashion and keep warm with answer the phone in winter Set-in MIC, available for cell phone to transmit the speaking phone to your audio devices directly so that the user can hand free answering Set-in Li-ion chargeable battery, charge via USB Cable, long stand-by time. V3.0+EDR Bluetooth version,available for most of devices with bluetooth function. Speakers can be taken off so that you can wash the hat