To facilitate typewriter use in business settings, a tab (tabulator) key was added in the late nineteenth century. Before using the key, the operator had to set mechanical "tab stops", pre-designated locations to which the carriage would advance when the tab key was pressed. This facilitated the typing of columns of numbers, freeing the operator from the need to manually position the carriage. The first models had one tab stop and one tab key; later ones allowed as many stops as desired, and sometimes had multiple tab keys, each of which moved the carriage a different number of spaces ahead of the decimal point (the tab stop), to facilitate the typing of columns with numbers of different length ($1.00, $10.00, $100.00, etc.)