Features:1.Using the latest bluetooth chipset V4.1.2.Sensitivity Microphone to ensure high quanlity calling.3.Innovative Bullet design，use for car/speakers/headphones etc.Specifications:Color:Blue，Black，Pink，Golden，SilverVersion:Bluetooth V4.1Product Length:54mmProduct Diameter:12mmCharging Voltage:DC 5VBatter Capacity:55mACharging Time:2 HoursWorking Time:5 HoursCable Length:20cmPackaged included:1x Bluetooth Receiver1x Charging Cable1x User Manual(not included other devices)Usage:Basically:Power On: press MFB for 3s.Power Off: press MFB for 3sPairing Mode: press MFB for 6s(power off status)Exit Pairing Mode: devices will exit pairing after 150s if no actions.Shut Down: Automatically shut down if no connection in 10 minutesCalling Conversation:Answer Phone Calling: press MFB 1 time to answer callReject The Phone Calling; press the MFB for 1s to reject the callHang Up The Phone: press the MFB for 1 time to end conversationCancel Dialing: press MFB 1 time to cancel the dialingRedial Last Phone; press MFB 2 times to re-dial the latest phone to