Desktop Publishing Supplies Brand Red A4 Square Flap Envelopes are perfect to accompany 4" x 6" photos! These Red A4 Envelopes are made from a 24lb bond / 60lb text (90 gsm) Holiday red paper stock and are inkjet and laser printer compatible. These red A4 envelopes measure 4 1/4" x 6 1/4" each and feature a booklet style square flap.