There are a few stipulations for the shared and combined mailing, the customer insert must meet the size requirements for the envelope that the customer wants to use for the mailing and the maximum thickness of the insert is no thicker then 1/32 or .03125. There is a weight limit of .26oz on the insert for the shared and combined first class mailing. The minimum amount is 300 hundred inserts and there is no maximum amount for the mailing.
