American clipboard box.

Saunders of Maine have been making these clipboard boxes for over 50 years. They are widespread on the highway (popular with truckers and delivery drivers), in factories and on building sites. They are made from 1.2 mm thick lacquered aluminium which is robust in most circumstances (under pressure it might bend just a little). The boxes are so practical; beneath the writing surface (which has a very strong clip) and the detachable compartment for storing paperwork, there is still room for stationery items such as pens, notes, drawings, handbooks etc.