Desktop Publishing Supplies Brand White A2 Square Flap Envelopes are perfect to accompany our 2-up invitation cards, 4-fold greeting cards, or 4-up postcards! These White A2 Envelopes are made from a 28lb bond / 70lb text (105 gsm) white paper stock and are inkjet and laser printer compatible. These white A2 envelopes measure 4 3/8" x 5 3/4" each and feature a square flap.