Product details of M27 Tws Wireless Earbuds Touch Control Waterproof Sports Gaming Headphone In Ear M27 Earphones With Powerbank.1.Bluetooth specification: V5.3  2.Bluetooth Profile:A2DP, AVRCP, HFP, HSP 3.Working voltage:3.1V-4.2V 4.Charging voltage:5V-1A 5.Speaker specification: 8mm*2 6.Frequency response: 20Hz-20kHz 7.Impedance:320 8. Battery capacity of the headset: 50MAH 9. Battery capacity of the storage box:2000MAH 10.Transmission distance:>10-20M 11.Call Play time:About 4-6 h 12.Charging time of headset:1.5h 13.Charging time of the Charging box:2h