This is Bluetooth receiver module phone headset mp3 decoder board SD card fever level audio digital power amplifier board diy.
Bluetooth audio receiver module has aux audio input and mp3 SD card decoding, with digital amplifier output.
You can also answer the phone after connecting to the phone using bluetooth (hands-free function).
Voltage: 5 V input, B connection 3.7 lithium battery
Dimensions: 8.3×4.2 cm / 3.27×1.65 inches
If aux is not inserted after downloading, the default connection is Bluetooth. Insert aux automatically disconnect the bluetooth to the aux input.
You can automatically switch only one input at a time, and you cannot switch to 2 states at the same time.