I would assume, but they fitted it for my ear and did all the auditory tests, so I would assume they calibrated for my hearing and stuff as well. I’m also not one to really want to wear that out in public, which furthered my dislike for it. As far as effectiveness, I didn’t think it helped that much, given I only tried it for a few hours around campus. I still stuttered while using it, but occasionally I would be more fluent in certain situations.