100% acrylic yarn with a plastic button to fasten and a faux leather tag. This sleeve is great for your taller books. Its max capacity is a hardcover 9.5 inch x 6.5 inch x 1.25 inch (about 340 pages) book. It can hold thicker books easily if they aren't as wide. For example, it easily fits a 450 page book that is only 5 inches wide.
