Feature:1. With AUX + for Bluetooth audio input, subwoofer + left and right channel output2. The power amplifier chip has AM interference suppression function3. The protection mechanism includes overvoltage, undervoltage, overheating, DC detection, and short circuit protection, which is relatively safe4. Using high‑quality materials, strong and durable, has a long service life5. With small size, easy to carry and store, convenient to use and with good performanceSpecification:Item Type: Power Amplifier BoardProduct Model: ZK-TB21for Bluetooth Version: 5.0 (Unobstructed: Approx. 10meter / 32.8ft)Input Sensitivity: 500mVInput Method: AUX+ for BluetoothNumber of Channels: 2.1 channelsPower Amplifier Chip: TPA3116D2 (with AM interference suppression function)Adapter Power Supply: DC 12-24 V/5A or more (the higher the voltage, the greater the output power)Adapted Speakers: 20-100W, 4-8Output Power: Left and right channels <50WSubwoofer <100WProtection Mechanism: Overvoltage, undervoltage, overheating, DC detection, short circuit protection.Package List:1 x Power Amplifier Chip2 x Power Amplifier Board Module1 x Screw Accessories Pack1 x Screwdriver Accessories Pack