Lin Fang-jhou points out that most bookbags are made from eight- to 10-ounce canvas, but bookbags from The King are heavier at 12 ounces per yard. It's more expensive, but more wear-resistant and less affected by a heavy load of books, and buckles don't pull loose from the thicker fabric after the bags have been used for a while.
林芳洲指出，坊間書包多半用「一碼重 8-10 盎斯」的帆布，但書包大王所用的帆布因密度高，每碼則重達 12 盎斯，雖然成本較高，但卻耐磨、耐重，也可讓布與銅扣之間的咬合度更為緊密，即使用久了銅扣也不易鬆脫。