If you're taking your phone under the water to snap photos, or need it with you when you'll be going swimming or boating, look up its IP code. IP is short for International Protection, and the higher the number, the more protection you get. Most phone cases are rated IPX6 to IPX8, with IPX8 (up to 100 feet down for two hours) generally being the highest. If you're wondering about the X, it's for particulate matter, and means there's no data. Unless you vacation at a chemical plant, it won't be an issue.