K22 4 Mics TWS Bluetooth Wireless Earphone

Bluetooth version: Bluetrum 8925B V5.2
Bluetooth protocol: A2DP/AVRCP/HFP/HSP
Audio decoding: AAC/SBC
Effective distance: 10m
Frequency response range: 20Hz-20KHz
Rated input: 3.7 V 250mAh (charging box)
Working hours: about 30 hours of playing time
Charging time: about 1h
Working temperature: -10~55℃