Pen case that fits a field notebook

A pen case made from 100% cotton #10 paraffin-coated waterproof canvas. **Regarding the water repellency of the "Pure Cotton #10 Paraffin Waterproof Canvas" used for the main material:** https://www.youtube.com/shorts/Lfetja_Ky2g This material is highly durable and may feel stiff at first, but it softens and conforms with use, allowing you to enjoy its __aging process.__ Products will have creases (white lines) from the sewing process. This is an inherent characteristic of the paraffin coating and not a defect in the fabric. The zipper is a __YKK 3 coil__, and the __elastic cord, a design highlight, is also a reliable industrial product__, ensuring __long-lasting quality__ without easy deterioration. https://live.staticflickr.com/65535/54795476673_31865fa1bb_w.jpg The product measures a __practical 20cm in height and 13cm in width__ when folded. The two zipper pockets on the left are free spaces, perfect for organizing accessories like erasers and pencil lead cases, as well as a 16cm ruler. The right side can hold up to two field notebooks (also fits A6-sized notebooks). **Note: The notebooks and stationery, such as pens, shown as storage examples are not included.**