NO-SLIP GRIP Backing provides longer sheet life -7 times longer than conventional sandpaper. It also finishes faster and helps reduce hand fatigue. For the best sanding results, sand with the grain of the wood and work through a sequence of grits, from coarse to ultra fine, skipping no more than one grit between sanding steps. This medium, 120-grit, sandpaper smooths wood grain. The purple colored abrasive will NOT discolor the surface you are sanding and has an anti-load coating for long life. Use sheets of sandpaper by hand, on a sanding block, or cut it to size for a power tool sander.