What do you mean by UV-stabilized?
Unless specially treated, most plastics will gradually break down from prolonged exposure to sunlight. This is especially true of transparent plastics, which quickly go yellow.
All our case materials are UV-Stabilized so they will not break down in sunlight.
Note: Although the material itself is protected, the case will not protect its contents from harmful rays. Electronic equipment should never be left out in bright sunlight - not even in an Aquapac!