Overview: BT 5.1 technology brings high-speed data transfer speed, stable performance, and low power consumption. With true wireless stereo technology, you can use the headset solely or used them in pairs. Equipped with a 200mAh charging box to store and charge the earbuds. Built-in Microphone delivers a clearer and more realistic sound. It will bring you a perfect user experience. Specifications: BT Version: 5.1 Transmitting Distance: up to 10m (no obstacle) Drive Diameter: 10mm Frequency Range: 20-20KHz Speaker Sensitivity: 98dB Impedance: 32Ω Charging Case Battery Capacity: 200mAh Earbuds Battery Capacity (Each): 30mAh Music Play Time: about 3.5 hours (depends on music volume) Earbud Charging Time: about 1 hour Charging Box Charging Time: about 1.5 hours Color: Black Earbud Weight (Each): 3g/0.1oz Package Size: 10.0*9.8*3.0cm/3.93*3.85*1.18in Package Weight: 62g/2.18oz Package List: 1 * Pair of Earbuds 1 * Charging Case 1 * Charging Cable 1 * User Manual (English/Chinese)