If you want to add mapping to the unit, you have to purchase a map card. The Helix 7 can only use the microSD size cards. The maps are on the card when you purchase them.
The unit will read Lakemaster and Navionics map cards. The current issues of both are microSD and come with an SD adapter to use in units with SD readers.
Before you purchase a map product check the coverage they have to see if your waters are included.
You view the current Navionics maps on their website by selecting Web App.
You can download the Lakemaster lake list from the Humminbird Lakemaster site.
Humminbird Helix 12 CHIRP SI, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2, SOLIX 12 SI, 360, RC-1