This field in the Bin Label report (RBL) is only available when you select the Price Change File as the "File to Use." The purpose of this field is to allow you to add RBL to a daily queue to print labels for price changes whose effective date is X number of days away. For example, a daily RBL using the Price Change File with ‘Days before Effective’ set to 1 will print labels for price changes whose effective date is tomorrow.
When printing the Bin Label report (RBL), if you select Label to Use "Generate File for Label Manager," then in this field, select the number of days before price changes become effective to create label batches.