Some tips if you use electrodes :
If you want to increase the intensity (amount of current flowing) but the output voltage of your device is low (the F165 or the F125 output 12V if i remember correctly ?), what you can do is :
->Increase the wetness of the skin and of the electrodes (i put cotton clothes around my electrodes, and i put salt water on the cotton clothes.)
->Increase the contact area between the electrodes and the skin
->Increase the pressure (not too much) of the electrodes against the skin.
In theory, a higher intensity helps the signal to reach more parts of the body with a high enough remaining intensity and thus can impact the harmful organisms with more "power" (harder shakes).