Pratt PRA0058 Recycled Corrugated Cardboard Single Wall Standard Flat Box with C Flute, 12" Length x 12" Width x 3" Height, (Pack of 25) ((Set) of 3) 100 percent recycled corrugated box for packing, shipping, and storing 32 ECT grade for standard stacking performance Flat square shape fits frames, books, or other flat items Made of single wall C flute corrugated fiberboard with standard kraft color