2 PCS Electronic Accessories: 1 x 2.1 channel preamplifier board & 1 x MP3 Bluetooth Decoder Module Maximum Power Per Channel: NO POWER Channels: 3 (2.1) The product is a finished product colour:red+blue Material:PC + Metal MP3 Bluetooth Decoder Module: Model Number: MP3 Bluetooth Decoder Board Loss Power Supply: 3.7-5V SNR: 90dB + N: -70dB Crosstalk: -86dB DNR: 91dB Support Profile: A2DP / AVCTP / AVDTP / AVRCP / HFP LOS:more than the 15m USB powered Universal Micro- USB 5V power supply 3.7-5V Supply Pad External 3.7-5V lithium battery power conversion LED indicator Bluetooth mode long blue light 3.5mm stereo audio interface Standard 3.5mm interface, output stereo , plug in headphones, connect amplifiers and other devices After the power is turned on, the blue indicator lights up and enters the Bluetooth mode; the English "The bluetooth device is ready to pair" is displayed, indicating that the Bluetooth mode is entered and waiting for pairing; the "XY_BT" searched by the mobile phone Bluetooth is the device name of the decoding board. , Click on the connection, the decoder board prompts "The bluetooth device is connected successfully", indicating that the decoder board and the mobile phone are connected successfully, you can . As shown below Picture; 2.1 channel preamplifier board: size:98 x 40mm Package Contents: 1 x 2.1 channel preamplifier board 1 x MP3 Bluetooth Decoder Module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.