Features 1、Sound adjustment: support high/medium/bass EQ adjustment, enhance +15dB and attenuation -15dB, support left and right channel balance adjustment, suitable for tone adjustment. 2、Three sets of stereo mixed input :3.5mm+6.5mm+RCA. 3、Provides three sets of stereo output simultaneously:RCA+RCA+3.5mm. 4、Independent Toner Audio Control: With independent audio source channel high/middle/bass control. Attenuations -15dB and +15dB gain, the sound adjustment design allows you to adjust the audio independently and control the output volume independently. 5、Simple installation: input and output plug and play easy installation, enjoy music instantly. 6、USB 5V power supply, suitable for outdoor mobile power use, with wider application range. 7、Compact and desktop design, and can be compatible with any devices. Specifications: Features: Sound adjustment: support high/medium/bass EQ adjustment, enhance +15dB and attenuation -15dB, support left and right channel balance adjustment, suitable for tone adjustment. Three sets of stereo mixed input :3.5mm+6.5mm+RCA. Provides three sets of stereo output simultaneously:RCA+RCA+3.5mm. Independent Toner Audio Control: With independent audio source channel high/middle/bass control. Attenuations -15dB and +15dB gain, the sound adjustment design allows you to adjust the audio independently and control the output volume independently. Simple installation: input and output plug and play easy installation, enjoy music instantly. USB 5V power supply, suitable for outdoor mobile power use, with wider application range. Compact and desktop design, and can be compatible with any devices. Specifications: Material: Metal Input channel: 3-way stereo input 3.5mm+6.5mm+RCA interface Output channel :3.5mm/RCA interface Input impedance :100K Ohm Output gain: high, medium and low -15dB and +15dB Frequency response: 20Hz-20KHz Signal to noise ratio: more than 107dB Total Harmonic Distortion: less than 0.08% Intermodulation distortion: less than 0.01% Charging Connection: USB 5V Item Size: 130 * 77 * 38mm / 5.11 * 3.03 * 1.49in Item Weight: 380g / 13.4oz Package Weight: 530g / 18.69oz Package Size: 20 * 18.5 * 5.5cm / 7.87 * 7.28 * 2.16in Packing List: 1 * Stereo Preamplifier 1 * USB power cord Package List 1 * Stereo Preamplifier 1 * USB power cord