Size: Fits for head circumference 56-58cm Speakers can be taken off so that you can wash the hat Transmission distance: 30ft or so; Transmission distance of MIC: ¡Ü3 ft; Li-ion Battery:3.7V/100mA; Charging time:2.5 HRS; Standby time: 60 Hrs; Continuous working time: about 3.5Hrs Suitable for various occasions, such as sports and traveling package included: 1 x Headband 1 x Charging cable 1 x Instructions