The Oslong advantage is the hidden super coated aluminum oxide corundum. The difference between it and other conventional coatings is that conventional discs have two layers of sanding surface, during sanding, the outer layer on the sand paper falls down together with the sanding product’s dust causing premature clogging. However, Oslong L338 has a hidden anti-clogging coating. This coating causes it to last longer than all other traditional sand paper including the best 3M discs. Furthermore, the proprietary film backing causes a very strong bond between the abrasive and the film backing adding to its long life. Finally, the film backing and the abrasive is very even, much more so than conventional paper making it much more effective during the entire sanding process. Box of 100 Oslong Green Film Velcro Hook and Loop Sanding Discs 40 Grit