Gold-A302B Amplifier Board 
A separate product identified is a small amplifier circuit board, often sold online for DIY electronics enthusiasts. 

• Type: This is a mono 1.1 channel Bluetooth 5.0 power amplifier board, which requires external speakers and power supply.

• Specifications: It runs on 8V to 24V DC input, delivers a total power of 30W, and uses the TPA3110D2 amplifier chip. It includes controls for bass and treble adjustments.