FeaturesV3.0+EDR Bluetooth version、 available for most of devices with Bluetooth functionFashion designed and also can keep warm on cold daysBuild-in MIC and 3.7V/100mA Li-ion batteryAllows users to hand-free answer phone General SpecsBluetooth V3.0+EDRFrequency 2.402-2.480GTransmission Distance 10MLi-ion Battery 3.7V/100mA Charging Time 2 hoursStandby Time 60hoursContinuous Working Time About 3.5 hoursPerimeter 40cm (flexible)Package DetailsWeight: 130.54 g Size: 24*22*2 cm