Blanc Couture A6 Regular Size 6-Hole System Planner Noir (Black) Ring Diameter: 15mm I tried inserting refills, but it felt too large to carry around, so I immediately put it in the included non-woven fabric and stored it in a dark place. There are some scratches that appear to have occurred during manufacturing, so please check the images. Please understand that this item has been stored at home before purchasing.