Features:
V3.0+EDR Bluetooth version， available for most of devices with Bluetooth function.
Built-in microphone， available for cell phone to transmit the speaking phone to your audio devices directly， hands-free answering.
Built-in Li-ion chargeable battery， charge via USB cable， long stand-by time.
Headphone can be taken off so that you can wash the hat.
Allows you to keep your music where it belongs - in your ears.
You will look great and keep warm while listening to your favorite music. Keep the sound track to your life playing all the time.
Perfect for traveling， waiting for the bus， jogging in the cold or just rocking out in your bedroom.

Specifications:
Bluetooth version: V3.0+EDR
Frequency: 2.4026GHz-2.480GHz
Transmission distance: 10M / 32.80ft
Transmission distance of Mic: ≤1M / 3.28ft
Li-ion battery: 3.7V/160mA
Charging time: 2 hours
Number of charge: > 1000 times
Charging voltage: DC 5V
Standby time: 60 hours or so
Continuous working time: about 3.5 hours
Size: Fits for head circumference about 43 to 68CM

we also have bluetooth hat