"DD" wrote in
:

The last 3 digits of these 8 characters will be
capital ACC. Examples: 12345ACC or A4B3CACC. I need help
with the input mask.

If the ACC is always going to be ACC, then don't store it at all:- just use
the Format property to stick it on in the text box.

If the ACC might change, and if it means something, then you probably
should be storing it in a separate field anyway, and concatenating them in
the textbox on the report or the form.

HTH


Tim F