Feature:1. Potentiometer Control Volume: Potentiometer works for adjusting the volume, come with switch, convenient to control the volume, very suitable for DIY speakers2. With Filter Inductor: Amp board come with filter inductor, the sound is round and clear, very practical3. 1.2MHZ Modulation Frequency: TPA3116D2 is a class D power amplifier IC launched by for TI, with very high index parameters. Up to 1.2MHZ modulation frequency, high power output distortion is less than 0.1%4. 2 Input Methods: With AUX and Bluetooth two audio source input methods, two in one, convenient to use5. Higher Efficiency and Longer Distance: 5.0 Bluetooth version possess higher transmission efficiency, longer transmission distanceSpecification:Item Type: Audio Amplifier BoardMaterial: PCBPurpose: Power amplifier boardModel: ZK-502CChip: TPA3116D2 (with AM interference suppression function)With or Without Filter: Yes (the sound is more round and clear after filtering)Adapted Power Supply Voltage: 5-27V (you can choose 9V/12V/15V18V/24V and other adapters, high power recommended high voltage)Adapted Speakers: 30W~200W, 4Ω-8ΩNumber of Channels: Left and right dual channels (stereo)Bluetooth Version: 5.0Bluetooth Transmission Distance: Approx. 15meter / 49.2ft (unobstructed)Protection Mechanism: Overvoltage, undervoltage, overheating, DC detection, short circuit protectionPower Supply Voltage: 12V 8 ohm speaker/12W (left channel) + 12W 4 ohm speaker/20W + 20W (right channel)15V 8 ohms/18W + 18W, 4 ohms/more than 30W + 30W19V 8 ohms/32W + 32W, 4 ohms/more than 45W + 45W24V 8 ohms/38W + 38W, 4 ohms/more than 55W + 55WTip: If the audio input is sufficient and the power supply voltage and c