HiFi Headphone Amplifier, It supports most headphones of high impedance 16-300 , 3.5mm AUX Input and Output, signal-to-noise ratio> 100Db, THD + N = 0.0003%, fully filter noise, enjoy high-quality audio. Bluetooth 5.0 receiver, It is designed to deliver studio-quality sound to your ears through wireless Bluetooth 5.0 technology-suitable for your existing wired headphones, earphones and even speakers. Rechargable Lithium Battery, It adopts a rechargeable lithium battery, which allows it to stay working about 13 hours. Plus, there is a volume control knob for volume adjustment. Two-stage Gain Switch, It enhances the signal input into the amp circuit for the optimal performance of the headphones. Make it Possibility to output not only louder sound but a sharper and more Real stereo sound without distortion Broad Compatibility, This amplifier is remarkably compatible with a variety of digital devices, such as MP3, MP4, Mobile Phone, Computer, CD players and personal media player.