U-Haul set the standard by requiring all the boxes we sell to have a minimum C-Flute structure. Importers, big box "discount" retailers and others pushing discount "moving kits" often offer boxes made with smaller B-Flute material, which is typically only 1/8" thick.  That's 25 % thinner than the C-Flute standard! In addition, specific kitchen, electronics and other specialty boxes are also double-walled for added strength to protect your personal possessions.    All  U-Haul Boxes are made to precise standards from the strength and flute structure of each box to the specific sizing that allows our customers to take advantage of easy loading and proper stacking while moving or used for storage.