The pocket version of the Florida saltwater species guide.
Regulations are species-specific and enforcement does not accept a good-faith guess. Telling a gag from a red grouper, or a mangrove from a mutton snapper, decides whether you are legal — and those distinctions are not obvious to anyone still learning.
The small format is the point. It fits in a tackle tray, a pocket or a glovebox, which means it is actually with you rather than at home on a shelf.
Get the large card for the boat and this one for the bag.