[Latest Bluetooth technology] The Bluetooth beanie supports Bluetooth V5.0 communication and Bluetooth music, and is suitable for most Bluetooth-enabled devices. Just sync to any Bluetooth device in a few seconds, hands-free connection, including rejecting/answering calls and listening to music wirelessly, up to 33 feet (10 meters).[Excellent battery performance] The Bluetooth Doudou headset has a built-in lithium-ion battery and a micro USB charging function. It only needs 2 hours of charging time to achieve 8-10 hours of Bluetooth talk/play time and 10 hours of Bluetooth music time. You have less time to charge and more time to enjoy music and calls.[Washable material] The wireless bluetooth cap can be completely washed, unisex, stretchable, one size fits all sizes and shapes. Thicker and higher-quality knitted materials keep warm, which is very suitable for best friends. Good workmanship, comfortable and warm. Does not fall off, deform, or shrink.