User Manual Click here to openFor different needs of customers we offer 3 versions for you to choose from Function ModelM18 Product ID 1476791 M28 this item M38 Product ID 1486746 Micro power supplyAudio headphone jackBuilt in amplifier 5W 5W Lithium battery poweredSupport USB sound card free driveVolume memory adjustmentMUTE mute interfaceButton extensionBluetooth versionbluetooch V4 2Support Bluetooth protocolHFPV1 7 A2DPV1 2 AVRCPV1 5 AVCTPV1 2 AVDTPV1 2Format supportSupport WAV WMA FLAC APE MP3 lossless decoding stereo two channel outputOperating Voltage5V 3 7V 4 2VBroadcast status not connected5 5MAConnection working status20MADeep sleeping3UATransmission distance20 meters empty or low interference environment Operating temperature 40C to 85CSensitivity 87dbmIntroduction This product MH M28 is a low power Bluetooth design solution supporting the latest Bluetooth 4 2 transmission two channel stereo lossless playback Bluetooth connection after the module is connected to Bluetooth very convenient In an open environment the Bluetooth connection distance can be up to 20 meters Widely used in a variety of Bluetooth audio reception a variety of audio DIY modification Pin numberPin headerDescription15VPower positive 5V2GNDNegative power supply3VBATLithium battery positive 3 7 4 2V4LLeft channel output5RRight channel output6AGNDAudio groundFunction Description Bluetooth V4 2 version supports Bluetooth automatic connection technology supports WAV WMA