This hifi amplifier board adopts 4 channels to provide you with a Hi-Fi stereo sound. High sensitivity makes sound very clear with no noise. And high output power of 4*50W produces a shocking stereo surrounding sound. Furthermore, built-in multi-level protections ensure safety. IC smart cooling system dissipates high heat rapidly and quietly. Features: 4 Channels - It adopts 4 channels to create a stereo surrounding sound. Gives you greater hearing enjoyment. Hi-Fi Stereo Sound - Maximum output power of 4*50W gives you a Hi-Fi stereo sound. Make you feel you are at the music world. High Sensitivity - Adopting high sensitivity to make sound very clear. Multi-level Protection - Built-in over voltage protection, over heat protection, undervoltage protection, DC detection and short-circuit protection of this digital power amplifier board helps provide a safe amplification. IC Smart Cooling - When temperature exceeds 25℃, fan will be turned on automatically to dissipate high heat rapidly and quietly. Stable Current - This digital power amplifier board makes sure a stable current, thus ensuring the stability and smoothness of sound. Specifications: Product type: HiFi Amplifier Board Maximum output power: 4*50W Output impedance: Supports 4-8Ω Channel number: 4 channels Input impedance: 10K Ω Power supply: DC 12-16V Protection: Over voltage protection, over heat protection, undervoltage protection, DC detection, short-circuit protection Package size: approx. 10 x 8 x 2 cm/ 3.9 x 3.1 x 0.8 in Package weight: 119g/ 4.2oz Package List: 1 x HiFi Amplifier Board . Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.