What can you do back on the beach between dives? Maybe your loved ones are strolling the beach while you're out diving. Either way when you are visiting the Tropical Atlantic, Caribbean or Gulf of Mexico this I.D. Card is a must. Know what you are looking at when you see it. This 6 X 9-inch plastic slate depicts 60-plus shells in color drawings, hole-punched to secure a lanyard for underwater use.