[2-in-1] High quality power amplifier board. With AUX and Blue tooth two audio input methods, 2-in-1. 5.0 Bluetooth version, the transmission efficiency is higher, the transmission distance is farther[High Performance] Blue tooth audio amplifier module 2.1 channel, Max output power 2X50W+100W. With antenna and antenna base, the signal is better, the efficiency is high, and the anti-interference ability is strong[Protection Mechanism] With short-circuit protection as well as overcurrent, overheating, and anti reverse connection protection to prevent total failure. In the event of an overload, the device reports the fault condition to the processor to protect itself from damage[High Quality] It adopts copper DC connector and fence type terminal. It can withstand large current, no heat, no damage to the wire. Free DC head lead, compatible with the input power interface of this product, even if you don't have a DC head adapter or battery, it can be easily wired[Application] With bass, treble, subwoofer frequency and volume control, easy to adjust volume, enjoy the music tone what you want. Widely used in store solicitation, home theater, square speakers, etc Parameter Model: ZK-MT21 Blue tooth Version: 5.0 (without occlusion 15m) Audio Input: AUX + Bluetooth Channel: 2.1 Input sensitivity: 500mV Adaption Supply Voltage: 12-24V / 5A above (Do not connect to 24V battery pack) Speaker: 20-100W, 4-8Ohm Output Power: max 50W @R&L channel; max 100W @subwoofer Protection Mechanism: anti reverse connection, overheating, overcurrent, short circuit protection Tip: To have enough output power if the audio input is sufficient and the supply voltage/current is sufficient. The power supply voltage is higher and the relative power will be larger. The speakers with different impedances will have different output power. In the case of sufficient voltage and current, the larger the ohms of the horn, the smaller the relative sound power. Please ensure that the power of the adaptor is greater than the actual working power of the amplifier.What you get:1 * Amplifier board blue tooth 5.01 * Shell (upper+lower)1 * Antenna+base1 * Accessories as shown