7 1/2 X 7 1/2 Square Envelopes. 70/28lb. Bright White (25 Per Pack) 7 1/2 SQ Invitation White Envelope - 28/70lb Regular Gummed Flap. The outside dimension of this envelope is 7 1/2 x 7 1/2. Perfect for Greeting cards, Weddings or any announcement.