B7 true wireless semi-in-ear bluetooth headsetSpeaker size: Φ13.2mmHeadphone size: 40X18X16mmCharging compartment size: 61X46X25mmBluetooth version: 5.0+EDRBluetooth support: phone hands-freeFrequency response range: 20HZ-20KhzBluetooth support protocol: AVRCP/A2DP/HSP/SPPTransmission frequency: 2. 4GHZ-248GHZBluetooth receiving effective distance: 10mBattery capacity: 30mAhWith microphone: omnidirectionalBluetooth working time: continuous playback 4-5hBluetooth standby time: 100HInput voltage/current: equipped with dedicated charging compartmentCharging the headset in the charging compartment: 4-5 timesCharging warehouse standby time: 60 days