USPS Tabbing / Wafer Sealing Requirements

The post office has specific requirements regarding FSM - Folded Self Mailers (bifolds, trifoldsor zfold mailers) basically any mailer that requires the use of a tabs to keep it closed during the mailing process. Self-Mailers prepared for automation rate mailings must be tabbed (secured) to prevent an open edge from jamming high-speed processing equipment. Standards for tabbing are based on basis weight of paper stock used and the location of the folded or bound edge.Tabs should be placed on the top or the sides of your mailer

  • Tabs should not be perforated
  • Minimum size of tabs should be 1
  • Letter sized bulk mailers require at least 2 tabs
  • Tabs are not required on flats

When using tabs on basic folded self-mailers the following applies:

  • Mailing pieces Up to 1oz require 2 tabs at 1” dia.
  • Mailing pieces Over 1oz require 2 tabs at 1-1/2” dia.
  • Tabs can be positioned in 2 places, see images below.
tabbing img tabbings img

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