The Ford F-Series includes a range of trucks from the light-duty F-150 to the heavy-duty F-750. Historically, Ford has used numerical designations in the F-Series to indicate the weight class and intended application of the trucks. For instance:
The F-750 is a medium-duty truck designed for commercial use, like towing and hauling in industries such as construction and utilities.
The F-650 is another medium-duty truck with similar applications.