Diablo's premium 6-7/8 -inch ALTO Sanding Disc with Hook and Lock backing includes break-through innovations that improve performance, extend sanding life and increase productivity. Featuring a premium zirconium blend, these discs remove material faster than other sanding discs and offer an extra long sanding life. Clog-SHIELD, Diablo's own blend of grinding agents, reduces loading thus maximizing productivity. The superior grit-to-backing bond, ENDURA-BOND, provides Diablo's sanding discs with longer life and extreme durability. Designed for use with ALTO sanders, these discs are ideal for sanding all types of wood.