All files are contained in a zip archive. Inside the archive there will be a vector EPS (Adobe Illustrator version 8+ compatible). Some Artists include a PDF and .AI as well. This is not compulsory. If the file contains any native CS features (e.g. gradient mesh or transparency), the native CS (Illustrator 11) file will be included if indicated in the file details next to the preview (e.g. “CS file included”).