6-Hole Ring: This notebook mechanism replacement kit is a 6-hole ring, and the ring is easy to open and close, making it easy to use. Steel Material: This product is made of steel material, it is very strong and sturdy, and smooth to the touch. Size and Quantity: The size of this product is 227mm long, 20mm wide, and the inner diameter is about 25mm; you will receive 4 sets at the same time, each 1 set comes with 2 pairs of screws and 1pcs clip ring binder. Easy to Use: You just fix the screws on your A5 notebook and then you can add the corresponding paper, it's very easy to use. Widely Application: Perfect for DIY planners, diaries, travel journals, notebooks, handbooks, personal organizers, study notes and data logging books, and you can also use it to DIY notebooks for your friends or family.