August EPA20 &ndash; Bluetooth Headphone Hat - Winter Beanie Hat with Bluetooth Stereo Headphones, Microphone, Hands Free System and Rechargeable Battery Bluetooth Hat  Keep warm while listening to music from smartphones and tablets Audio, Volume and Call control Buttons - Answer calls & control your music Built-in Microphone  Stay connected to your phone with hands free calling Internal Li Ion Battery  Rechargeable battery gives up to 6 hours between charges Thermal Hat  Warm your ears with your coolest tunes