Review on Navionics Msd Nav Ni Map by Jeff Kersey

I bought this product for a Humminbird Helix 7 sonar, as it covers all of North America I think it's a very good deal is. I fish from Wisconsin to Alabama and my other Humminbird 587 only has a Southern chip and costs more. This chip came with one year of free updates, just plug the micro SD into the SD adapter and then into your computer. Go to the Navionics website and update; dead easy. I have found the depths to be accurate considering the difference in lake levels.