The 1st Light detects a Normal EMF field, what is always around us.The range is between 0 to 1.5 mG. The 2nd Light (GREEN) detects a Low Level EMF,which range is between 1.5 to 2.5 mG. The 3rd Light (YELLOW) detects a Mid Level EMF in the range between 2.5 to 10 mG.
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