This is a cost-effective audio power amplifier specially designed for HIFI sound. Good quality with affordable price. Features: Made of good materials, delivers high performance. A cost-effective power amplifier for HIFI music. Employ TPA3116D2, a Class-D stereo amplifier IC with high performance. The modulation frequency can be up to 1.2MHZ. Equipped with BT 5.0, transmit farther and more efficiently. The potentiometer with a switch for easy control of the volume, making it ideal for DIY speakers. Integrated self-protection circuits including over-temperature and short circuit. Comes with DC , compatible with the power input interface of this product, even if you don't have a DC adapter or battery, it can be easily wired. Specifications: Material: ABS Color: Black Model: ZK-502L mini Chip: TPA3116D2(with AM avoidance) BT version: 5.0 Output power: 50W x 2 Maximum Power Per Channel: 50W Allowable supply voltage: 5~24V (optional 9V//15V/18V/24V adapter, high power for high voltage) Compatible speaker: 30W-200W, 4Ω,8Ω Number of channels: left and right dual channel(stereo) Transmission distance: 15 meters (without barrier) Protection measure: overheat protection, short circuit protection Power supply voltage: , 8Ω speaker/12W (left channel) + 12W (right channel), 4Ω speaker/20W +20W 15V, 8Ω/18 +18W, 4Ω/ greater than 30 + 30W 19V, 8Ω/32 + 32W, 4Ω/ greater than 45 +45W 24V, 8Ω/38 + 38W, 4Ω/ greater than 50+ 50W Item Size: 7.6 * 3.8 * 1.5cm / 2.99 * 1.49 * 0.59in Item Weight: 23g / 0.81oz Package Weight: 74g / 2.61oz Package Size: 11 * 6.5 * 5cm / 4.33 * 2.55 * 1.96in Note: 1. Only when the audio input is sufficient and the power supply voltage/current is sufficient, will there be enough output power. The higher the power supply voltage, the higher the relative power. The speaker with different impedance will have different output power. In the case of sufficient voltage and current, the larger the ohm of speaker, the smaller the relative sound power. 2. The switch on the board is for control of standby mode. When turn off the switch, the unit is in a low-power standby state. If you want to completely turn it off or you may not use it for a long time, you can just unplug the DC cable. Packing List: 1 * Amplifier Module 1 * Screwdriver 1 * DC 1 * Shell 1 * Knob