Theme park passes come in two forms.
If you are staying at a Disney resort and purchase your park passes at your resort, your pass information will be encoded on the magnetic stripe on the back of your room key (a "credit card", just like the key you got on the Disney Cruise line).
If you buy your passes at the theme park you'll get something only a little different. Those passes are also on a credit card-sized piece of plastic with a magnetic stripe on the back, but the material is much thinner and more flexible than a credit card. Some people think they're made of paper, but they're really a tough plastic material.
As long as that case can fit a few credit cards it'll be perfect for your WDW tickets.
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Co-Author, PassPorter Walt Disney World
http://www.passporter.com/wdw/