Designed by Naoto Fukasawa, SIWA cases are made of paper produced by the centuries old Japanese process of washi-suki. Recycled polyester fibers are added to ensure a durable product that is water-resistant, tear-resistant, and surprisingly strong. The pouch is zippered and the wide version is also great for storing cards.

The Naoron paper material is created by a team of expert craftsmen by blending a special mix of wood pulp and polyolefin to create a soft, crinkled-effect material that is water and tear resistant, and which can hold heavier contents with ease.

The slim size is meant for the minimalist who wants a pen case to hold one or two pens.