A5 Multi-Hole Ring Binder Hardware 20 Holes [A5-20-17R (17) SR] 1 Piece Multi-Hole Ring Notebook Binder Hardware A5-20-17R-17SR is a hardware that can be used with A5 size 20 hole loose-leaf paper. Ring diameter 0.7 inch (17 mm) is a slim size that can be stopped with one screw screw, a clamp, or rivet. This is a basic A5 notebook size, please check the size of the refill (paper) carefully before purchasing. Mounting hardware is not included and must be installed separately. Measurements are approximate. The color of the actual product and the color of the posted picture may differ depending on your monitor.