INPUT AND OUTPUT: The power amplifier board supports AUX+BT sound source input, and supports subwoofer + left and right channel output. EASY TO INSTALL: The stereo power amplifier board is easy to install and use, providing you with stable and fast connection and wide compatibility. ADJUSTABLE: This sound amplifier is enough to meet your different needs, you can adjust the frequency, volume, treble, bass, etc. PROTECTION FUNCTION: The high power amplifier board has anti reverse connection, overheating protection, overcurrent and short circuit protection. HIGH PERFORMANCE: The BT amplifier board 2.1 channel, BT 5.0, subwoofer, high power, stereo, suitable for 15‑100W, 4‑8Ω speakers.