as I have some tinnitus , I begin to have more trouble hear the alarm on my watch . I buy another watch but have the same problem - even try some in store . I buy this pq-10 about two year ago and have use it at home and travel all over the world to be awaken at all hour of the night . it have never fail . I think it be slightly lower frequency than wristwatch alarm , and it be louder - but not so obnoxious that my wife can not go back to sleep or neighbor in a hotel complain .