This SAE Standard applies to machines that are in regular commercial production. Included are the following categories: Earthmoving; Implements and Attachments; Agricultural Tractors; Forestry. In spite of the appearance of the same names, such as tractors in more than one category, further development of this and related standards will demonstrate that there are differences in the fully-equipped working machine that may require distinction as to intended end-point field usage. These differences include: Names of optional implements; Names of components of optional implements; Definitions of specification terms as affected by installed optional implements; Different mounting provisions on the machines for implements and other attachments; Differences in design to achieve objectives for performance, durability, or operator or public safety.