Does 4 Milli Siemens Equal 4000 Micro Siemens?

Yes, 4 milliSiemens (mS) is equal to 4000 microSiemens (µS). This is because 1 milliSiemens is equal to 1000 microSiemens. Thus, multiplying 4 by 1000 gives you 4000 microSiemens.