What is a CoLibri cover? A CoLibri cover is a transparent jacket that is custom-fitted over the book to protect it. They’re a better alternative to taped-on Mylar ® covers. What are the benefits of using CoLibri covers on my books? Your books will be protected from dust, dirt, water, UV rays, and day-to-day handling. The edges of a CoLibri cover are sealed shut, providing more protection than open-ended covers, and fit perfectly to each individual book. Clear, transparent jackets will not alter the book cover image. No glues or adhesives are used on the book itself. CoLibri covers work on any size or shape book, both paperback and hardcover. Your books will not stick together on the shelves because CoLibri covers contain a slip agent. Save money over time -- protecting your books now with cost-effective CoLibri covers will make them last much longer than uncovered books. CoLibri covers are non-toxic, odorless and waterproof. Go to My Specs in the menu and look for CoLibri under the Processing Options category.