beer and milk may be sold in crates but, contrary to popular usage, wine is sold in cases. A case typically holds a dozen bottles, the basic trading unit in the fine-wine trade and much of the wholesale wine trade. It has been posited that the case contains 12 bottles because that is as many as a man can comfortably carry. Most cases are made of cardboard outers, with cardboard vertical or papier mâché horizontal dividers. Wine merchants truly dedicated to the mail-order business ensure that they use only particularly strong cases especially designed to minimize breakage.