Universal -USB 5V power supplyExternal 3.7-5V lithium battery power supply modificationBluetooth mode blue light is onStandard 3.5mm interface, output stereo , can insert earphones, connect power amplifier and other equipmentSupport Profile A2DP/AVCTP/AVDTP/AVRCP/HFP.Pairing instructions: Connect to the power supply, the blue indicator light flashes, and enter the Bluetooth mode; when you hear "The Bluetooth device is to pair", it means that you enter the Bluetooth mode and wait for pairing; after the mobile phone Bluetooth searches for "XY-BT", Click Connect. When you hear "TheBluetooth device is connected successfully",It means that the decoder board is successfully connected to the mobile phone, and the blue indicator light is on, and the music can be played, and the blue indicator light flashes.size: 30 x 30mmMaterial:Electronic componentcolour:redPackage Contents:1 x Bluetooth Receiver boardOnly the above package content, other are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.