Desktop Publishing Supplies Brand Heavyweight White 6" x 9" Self Seal Envelopes are designed for customers looking for a higher end envelope for their mailings. 6" x 9" Envelopes are made for use with 5 1/2" x 8 1/2" invitations, half sheets of paper, or half fold greeting cards! These White bi-fold and flat card envelopes are made from a 28 lb bond / 70 lb text (105 gsm) paper. These White envelopes measure 6" x 9" and feature a square flap with an easy to use Peel & Seal Self Sealing strip!