The new Pen Holster fits all standard sized Notebooks, Bound Books, Field-Flex Books and Loose Leaf Binders. Perfect for keeping your writing utensil safe at hand! The Holster has an adjustable velcro and elastic strap for easy resizing. It also can double as a page holder or bookmark! You can also wrap the Holster around the exterior of your book to keep it closed in the field. Made with tough, black Cordura®. (pen and book sold separately)