Hook-and-loop sandpaper is similar to Velcro™ with the rough side called hook, and the softer side called loop. The “Loop” is on the backing of the sandpaper, whether that backing is paper, film, cloth or mesh. The “Hook” is on the back-up pad of an orbital or random orbital sander or the faceplate of a disc sander. These hooks and loops are used to attach the sandpaper to a machine such as a random orbital sander or disc sander. This makes it very simple to change the sandpaper. The Velcro keeps them secure and once positioned, they don’t move easily.