Like I said before, I received the LumiShadow for both my ear. I had figured, what the heck, for $120 I'll give it a shot. After for about one hour I sat down at my computer and ordered a second pair for backup! The right LumiShadow that I received had a persistent background hiss. I contacted LumiEar by e-mail with my problem, and they sent me a new right unit ASAP. The new LumiShadow works great!