Module stereo output, built-in Bluetooth antenna structure is simple, the power supply voltage is 3.7V~5V version selection, active speakers increase Bluetooth connection function. 7PIN output interface is spacing 2.54 through-hole, 7PIN output interface is: + power, ground, left a channel, right channel, mute, LED status indicator, reserved port. The LED state port is connected with a 100-ohm resistor in series, LED indicates the ground connection, the Bluetooth is not connected and the flash is fast. After the Bluetooth connection is successful, it is slow flashing. The volume is 30mm X 20mm X 3mm.