The 6 X 9 envelopes are an essential office supply. The 6 X 9 white booklet peel & seal envelopes are a great choice for sending greeting cards, annual reports, magazines, catalogs, and other documents that shouldn’t be folded. These envelopes are made using 28 lbs (104 gsm) stock paper for added durability. The high-quality paper allows users to insert heavier and thicker sets of documents without the worry compromising the integrity of the envelopes. This particular envelope type comes with peel & seal closure system. Users just need to peel the plastic strip, close the flap, and apply pressure to successfully seal the envelope.