Usage Tips:3.5mm interface: 3.5mm input interface takes 4-pole jack, output connects to headset with microphone, which can be used on mobile phones for normal voice calls, and another terminal with group lotus interface is available. Control range: 7-band equalization circuit control range 12dB, EQ band: 60Hz, 150Hz, 400Hz, 1KHZ, 3KHZ, 6.5KHZ, 15KHZ, by composition TI or ST TL074. Basic parameters: 7-band sound equalizer pre-amplification gain, classic 4580 op amp provides 5 times amplification (14dB); Input impedance 20K, output impedance 600 ohms. Compatible with Headphones: Sound equalizer ear amplifier part of NE5532 composed of 47 type headphone driver circuit, easy to drive all kinds of headphones, high and low adjustable. Aluminum Alloy: The 7-band car sound equalizer is made of aluminum alloy, high strength, corrosion resistance. corrosion, stable performance, DC5V-12V power supply, dual channel sound.