Examples: Gusset envelope; this envelope has a flexible base and a side gusset or fold, which can adjust to the contents. This makes this envelope suitable for sending larger items which vary in size. These envelopes are often made of strong kraft paper in up to 170 gram weight or in our Varaan specialty types, and have a gummed or self-adhesive flap. The gusset envelope is ideal for sending brochures, booklets, magazines and many other variable size items.