This is a handmade item created by myself using a home sewing machine. It uses a 20cm zipper, and the outer fabric is Liberty cotton linen lawn with quilt batting attached, giving it a soft and lightweight finish. The crane plant pattern in blue and yellow makes this a wonderful piece. Photo 6 shows the contents I actually put in a pen case of the same size (not included with the product). Please use it as a reference. I think a ruler up to 18cm would fit (the ruler in the photo fit). Besides a pen case, I think it can be used in various ways. Size (outer dimensions) Width: Approximately 22cm Height: Approximately 7.5cm Depth: Approximately 5cm Please allow for some margin of error. I make each item with care, but there may be some imperfections. I would appreciate your understanding and acceptance of handmade items. Thank you for your purchase. Thank you for your consideration. ◆When making a purchase◆ Please also take a look at my profile. ※Liberty Kazusa