It's made from a very sturdy nylon canvas and has a nice metal zipper. It unzips lengthwise, from mid-edge to mid-edge. Inside the case is a tri-fold pen roll, attached to the inside with nylon straps and metal rings. It is not removable. The pen roll has three pockets that cover the bottom third of the pens or pencils with another layer of nylon canvas, and an elastic strap that holds the tops of the pens in place. Each pocket can hold 4-5 pens, for 12-15 total. Inside the case is another mesh pocket with a Velcro closure. It's the right size for sticky notes, erasers, clips, washi, or lead refills. On the outside of the case is another pocket that can hold 2-3 more pens or pencils, for easy access.