I'm using navy tsumugi fabric. It's easy to use with a strap inside. A quilt batting is inserted inside, giving the fabric thickness and a soft, plump feel. - Material: Fabric - Internal structure: With a strap inside, the lining is green and red striped tsumugi. Main body size: 10cm x 9.5cm Strap length: 12cm Unused after creation. I make them carefully, but as a handmade item, please understand that there may be slight size errors, distortions, or misalignments. I look forward to your purchase if you understand!