Pack of 125 267x216mm Board Back Peel and Seal 115gsm Manilla Envelopes. These sturdy and durable board back envelopes are made from tough, heavyweight 115gsm paper and are perfect for mailing certificates, photos, artwork and more. The envelopes measure 267 x 216mm and feature a simple and secure peel and seal closure. This pack contains 125 envelopes.