Describe: Product Name: Bone Conduction Wireless Bluetooth Headset Color: black skin color Bluetooth protocol: HSP1.2, HFP1.6, A2DP1.3, AVRCP1.5 Rated voltage: 3.7V Transmission distance: 10 meters Headphone battery: single side 30mAH Charging box battery: 350mAH Package content: 1 pair of bone conduction wireless bluetooth earphones caution: 1. Please do not imagine the product size based on the picture, please purchase according to the specific size. 2.1 inches = 2.54 centimeters 1 centimeter = 0.39 inches 3. Please allow 1-3mm differences due to manual measurement.
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