Time-And-Materials Contract: A contract that provides for acquiring supplies or services on the basis of direct labor hours, at specified fixed hourly rates that include wages, overhead, general and administrative expenses, and profit; and materials at cost, including, if appropriate, material handling costs as part of material costs. A time-and-materials contract may be used only when it is not possible at the time the Task Order is executed to estimate accurately the extent or duration of the work, or to anticipate costs with any reasonable degree of confidence.