Upgraded Design: Add Bluetooth to a subwoofer amplifier. M01-BT support Bluetooth and RCA input can drive most home passive speakers, passive subwoofers, and powered subwoofers. (Note： M01-BT is not suitable for active speakers). Easy to build a simple sound system with M01-BT. Mini compact Class D Audio Amplifier: M01-BT SUB amp adopts ST Microelectronics TDA7498E high-performance chip, MAX power output up to 300Watts. Switch to PBTL(As a full frequency mono amp): You can use the banana plugs or bare wires to connect the passive subwoofer to the M01-BT, use the RCA cable to connect the powered subwoofer to the M01-BT. Switch to SUB(As a subwoofer amp): You can use the banana plugs or bare wires to connect the passive subwoofer to the M01-BT, use the RCA cable to connect the powered subwoofer to the M01-BT.