I agree with the wow. I purchased last fall and was blown away using on the big lakes. I have an LMS-520 on my boat with Navionics but I have it up front to use when fishing. I can see when running but to adjust when coming up on a spot is a real pain - zooming in / out or changing views. Now I use the iphone "on my approach" to structure and don't have the adjust problems. Great deal for just $10 IMO...

kc