Features:HiFi Headphone Amplifier, It supports most headphones of high impedance16-300Ω, 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,Itis 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.1500mAH Rechargable Lithium Battery, It adopts a rechargeable lithium battery with 1500mAH capacity, which allows it to stay working more than 8 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 distortionBroad 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.Specification：Lithium battery capacity: 1500mAHAmp using time: more than 8 hoursBluetooth decoding mode:SBC, AACBluetooth protocol: A2DP V1.3.1, AVRCP V1.6 ,HFP V1.7, HSP V1.2Bluetooth distance: 8m MaxAmp battery voltage: DC3.7V - 4VAmp internal working voltage: ±4VSNR>100DbTHD+N 0.0003%Adapted Headphone Impedance: 16-300ΩDimension: 96x61x15mm(L X W X H)Power Output:16Ω L: 90mw H: 105mw（Gain）32Ω L: 74mw H: 80mw（Gain）64Ω L: 45mw H: 50mw（Gain）150Ω L: 26mw H: 32mw（Gain）Note:For Iphone you are probably required to pair your phone with our headphone amplifier each time. Please follow below: Settings---Bluetooth---My Device, then click "Neoteck RX5.0" to pair.Package Contents:1 x Bluetooth headphone amplifier1 x USB Power Cable1 x 1m Audio Cable1 x User's Manual