The all new, Humminbird LakeMaster PLUS digital GPS map card series is a new family of map cards that parallels the standard Humminbird LakeMaster editions. Coverage area and lake lists remain the same and both are compatible with most Humminbird GPS models including the ONIX and ION units. PLUS has all of the features you've come to love from LakeMaster, but now allows for aerial image overlay on high definition waters. Now you have the ability to use quality aerial photography to view the entry and exits of creek channels, see how far a reef or weed line extends, pick out shallow water rock piles, steep drop-offs and other features of the lake you've been missing from traditional maps. LakeMaster PLUS gives you the freedom to choose how you want to use the aerial imagery. The Ariel Only layer shows only aerial imagery and no other map information. The Land Aerial and LakeMaster Map layer shows the LakeMaster map and the aerial imagery that extends around the body of water. The Full Ariel and Contours Overlay layer shows satellite over land and water and contour data overlay on water. The Humminbird LakeMaster PLUS Great Lakes Edition, Version 2, micro map card with SD adapter has added over 140 lakes since the prior version - 50 in High Definition - and boasts more than 380 lake maps in High Definition and over 1,540 total lakes from MI, IN and OH.