This is very easily done with a macro. You should be able to create a form with the options you want for dimension prefixes/suffixes. This will allow you to use one macro to add many different items to your dimensions (mm, in, ", diameter symbol etc). Use the selection manager routines to loop through all the selected dimensions and add the text as required using "Dimension.SetText". The advantage of using a macro is that it is not dependant upon dimension favorites. The api help already has most of what you need to do this. You just have to combine the selection manager examples with the dimension property example. You can also use the same routine to delete suffixes as well.