What is Impedance Control?

To make sure the quality of signal in complex design, we need to control the resistance and reactance of an electrical circuit.
Such as single-ended impedance 50 ohm ±10%， differential impedance  100ohm ±10%.

If you know what you want and need impedance control, please enclose the impedance requirement document along with the gerbers and select Yes.

If you don't know or don't need impedance control, I hope you can have a chance to select Yes for this option someday.