EVA Electronic Final Stabilizer FS-X I purchased this two years ago, but I haven't used it much, so it's been sitting at home. I'm putting it up for sale. It works perfectly and is in excellent condition. The box, instruction manual, and battery are included. Immediate purchase is welcome; price negotiations are not accepted. Thank you. This device matches the impedance between your effects board and amplifier, and the built-in transformer adds depth and dimension to your sound. The connection order is not at the beginning of your system, but right before the amplifier, at the end of your effects board. By doing so, you can restore the original thickness and brilliance of your guitar sound, which can be lost when using long cables or several effects. It picks up and expresses even the picking nuances and the sound of your fingers sliding on the fretboard, which you can only get when you crank up a tube amp. The volume doesn't matter. And if you're lucky enough to be in a location where you can crank up the volume for a live performance, the sound will pierce through to the player and the audience. The revived low end will become a ground-hugging bass that will move the listener's heart. It can be used with both guitars and basses. Microphones will pick up the sound better, and you'll be able to record with a sound you've never been able to achieve before in a recording environment. It is equipped with a phase (sound polarity) switch, allowing you to freely switch the phase of the sound emitted from the amplifier, enabling stable sound in an ensemble. ※While it seems to have similar functionality to the LoZ to HiZ Converter (FS-2), this unit doesn't just increase impedance. It creates a polished texture, like a mastered sound source. You'll clearly notice the difference between using it and not using it. ●There are some usage precautions. If you put a wah pedal in a group of true bypass effects, it may emit sound due to compatibility issues with the circuit. In that case, put our Stabilizer or similar after the wah to lower the impedance, or modify the wah (EVA wah MOD). The quality of the power supply greatly affects the sound. External power supply only DC9～18V (cannot use internal battery)