Lenovo QT81 TWS Earbuds - Black Specifications Brand Lenovo Category Earbud Product Type Earbud BT Version BT 5.0 Transmitting Distance 10m Drive Unit 13mm Frequency Range 20-20KHZ Sensitivity 98+3dB Impedance 320 Charging Box Capacity 3.7V 1200mAh Earphone Battery Capacity 2 * 3.7V 40mAh about 5 hours (depends on music volume) Music Play Time Waterproof IPX4