Features [Exceptional Sound Quality] The amplifier is equipped with high frequency electrolytic capacitors, has a circuit design for noise reduction and has no background noise, which can effectively amplify audio and improve sound quality. Adjustable volume: The amplifier has a volume control that allows the volume to be freely adjusted according to the needs of the user. [Wide Compatibility] The amplifier is largely compatible with all audio devices, and the input can be connected to DVD, CD, set-top box, MP3, TV, game console or other devices. The output can be connected to speakers, subwoofers, headphones, etc. [Portable and Compact] The amplifier is small, easy to carry and use, and can improve the sound quality of your device anytime and anywhere. [Aluminum Alloy Housing] The aluminium alloy housing of the amplifier is very robust, has good anti-interference and no signal loss. Specification: Product Type: Mini Stereo Audio Preamp Material: ABS and aluminium alloy. Input: RCA (L/R), 3.5 mm. Output: RCA (L/R), 3.5 mm, jack. Power supply: DC 5V Battery: 1000mAh 503450 lithium battery (built-in) Compatible input devices: DVD, CD, set-top box, MP3, TV, mobile phone, computer, tablet, record player, sound card, guitar, bass, electronic musical instrument, game console or other devices. Compatible output devices: speakers, subwoofers, sound blasters, reverbs, AV receivers, afteramps, headphones, etc. Size: approx. 87 x 50 x 37 mm / 3.42 x 1.96 x 1.45 inches. Package list: 1 x Mini Stereo Audio Preamp 1 x USB power cable. Package List 1 x Mini Stereo Audio Preamplifier 1 x USB Power Cable