I agree with ya'll; but, I can't imagine flying a full day ever again without my ANR helmet. Occasionally I unplug it just to remind myself of how it was before. After a few seconds I plug it back in and leave it alone. I have a spare set of internals just in case something quits I can switch them out and send the broke one's in for repair. High freq-low freq, im my mind it (and ears) it makes a differnce.
barryb