7-Hole Cover Set by HaloDex, Black, 9 x 11, Poly Poly Cover Set, 1 Front & 1 Back, material is a heavy duty .035 Polyethylene Material HaloDex notebooks have the same hole-pattern used by all major day planner manufacturers, which means you can fill them with any brand of preprinted calendar and all types of accessories HaloDex notebooks lay-flat & fold-back like spiral-bound notebooks and they allow pages to be added or removed like a ring binder HaloDex notebooks have the same hole-pattern used by all major day planner manufacturers. They can be filled with any brand of preprinted calendar and accessories Finally . . . an advancement in notebook technology worth noting!