single sided def (left ear unfortunately). Can't hear almost anything on the left side of me (including cars) without my baha which I can't fit on while wearing a helmet @ MVclyde no acoustic neuroma I hope! ( symptoms I had before I found out I had that tumor )... once it came out it only got a little better... still stumble sometimes and run into door frames if I am too close and/or its too dark, cycling has been a challenge with some intermittent weaving, but all in all pretty good lately.