Stereo Wireless Speaker Bluetooth 4.0 Audio Receiver Module For DIY Modified Speaker has a built-in Bluetooth module. The antenna structure is simple. The power supply voltage is 3.7 ~ 5V; active speakers increase Bluetooth connection function. The 7PIN output interface is spacing 2.54 through a hole; 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. Package Includes : 1 x Stereo Wireless Speaker Bluetooth Module. 1 x LED. 2 x Capacitance. 1 x Resistor. Category: Audio Module