Simply turn the dial to one of the magnetic settings and put the meter at the electronic gadget and slowly move the meter from the gadget until the reading is only 0-1 milligaus. That is the distance we must be from electrical objects to reduce harmful exposure to EMFs. When using computers, I suggest laptops over desktops. Laptops have much less EMFs but you have to use a separate keyboard and mouse that would be plugged into the laptop. Roller-ball-type mouses are non EMF-producing. Wireless and infrared mouses generate very high EMF-levels. I have not tested many headsets but headsets that I have tested all have magnets in earpieces that directly emit EMFs into ear and head. When you use the TriField meter, use Magnetic (0-3 range) and Radio to test each at the ear piece. If you get a higher than 1 miligaus reading, get a tube ear piece to move the magnet away from your ears and head. Consider also, that EMFs may be generated into your home from power equipment outside homes, including electrical generators. If you have a high EMF-field in your home that remains relatively constant after you turn off the power in your home, EMFs are generated outside your home. Get the electric company, electrician or landlord to fix it. Or, I suggest that you move to another home.