It has a material on the outside that has a really cool "wetsuit" feeling. Their cases are also well made and are high quality in my opinion. The sleeves are really great because they have these soft things that cushion the CDs. Also, the sleeves can be taken out and repositioned (you can't do that with most cases)!
These cases are definately the best I have ever seen and used! Easy to use and high quality! Only one problem, what do I do with all the jewel cases?