Powerful Earphone with Strong Magnetic Attachment Chips for crystal-clear stereo sound: Bluetrum AB5635B, BT 5.3 Frequency: 2.4GHz to 2.4835GHz; Dimensions: L48.2*W16.9*H17mm; Net weight: 14.6G 90mAh battery 20 hours are needed for charging. Standby time: 60 hours, working time: 11 hours