BH128 Bluetooth 5.0 Wireless Headphones Bone Conduction Earphones Outdoor Sport Headset with MicSpecifications:Color: blackBluetooth chip: QCC3003Speaker type: 1 watt bone conduction hornBattery: 120 mAh polymer batteryMic: anti-interference microphone, -36dbUser time: 4 hours of use (standard volume)Standby time: 15 daysEffective range: 20 metersMono/stereo: stereoBluetooth version: EDR / (QCC3003) 5.0Weight: 35.5gBluetooth Class (I/II): IIBQB included(Y/N): NoBluetooth Profile: A2DP/HFP, HSP, AVRCP, GAVDP, AVDTPReceive sensitivity: 84±3dBImpedance: 10 Ω ± 15% (AT 800 HZ)Frequency range: Fo-20KHzFM: NoCharging using the USB interface: for 1.5 hoursTF card: NoSystem language: English tipsIndicator statusRed light flashes quickly: low battery warningSteady red light: chargingBlue light is always on: fully chargedBlue and red alternately flash: BT matchBlu-ray double slow flash: no match, maybe the device is powered off, or the distance between the two is more than 20m. The blue light flashes slowly: match/dial/play audio.Basic operationOperation     control      prompt toneAnswer the call Click the multi-function button onceEnd the call Click the multi-function button onceReject the call, press and hold the multi-function button for one second.Call long press the multi-function button for one secondSwitch songs:  Press and hold the volume button "+" "-" onceVolume control: Click the volume button "+" "-" to make the volume smaller and largerPlay/pause phone music Press Multi-FunctionOpen and press the Power button for 3 seconds. Prompt/powe onClose Press and hold the Power button for 3 seconds. Prompt/powe offBluetooth disconnectedBluetooth connectionClear the match. Turn off the power and press the Power button for 6 seconds.Low batteryNotes:1. There may be slight size deviations due to manual measurement, different measuring methods and tools. 2. The picture may not reflect the actual color of the item because of different photographing light, angle and display monitor.