processing equipment at the U.S. Postal Service. Having your direct mail piece tabbed with wafer seals ensures safe processing, postal discounts and timely delivery of your direct mail advertisement by the USPS. It is essential to use tabs, wafer seals and glue strips for sealing mail booklets too. KD Mailing & Fulfillment can apply up to three tabs quickly and easily as part of our in-line imaging process for tabbing mail. Choose clear plastic, paper or customized tabs to complement the design of your mailing piece.