Just like the mail carrier of old, truck tool boxes have to be able to stand up to the ravages of the elements. You can get toolboxes made from heavy-duty plastic, heavy aluminum, and steel. For the aesthetically inclined tradesguy, there are boxes that sport a rugged-looking diamond-plate pattern. (Ooooh!) The most popular colors tend to be black, white, or the natural steel and aluminum colors. To get an idea of what's available, check out manufacturers online such as Deflecta Shield and Dee Zee.