What's in the box:

Stereo Preamplifier Preamp Stereo Toner High/Medium/Bass Adjuster 3-Channel Sound Mixer (Standard)

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