These envelopes are constructed from laminated fiberglass strands between kraft paper layers which adds extra tensile strength and superior protection against grease, water, and oil damage.
The laminated fiberglass reinforcements protect the bags against tearing, puncturing, and abrasion. Being unpadded, these reinforced bags cost less to mail.
Self-sealing style has an end flap that is coated with a natural rubber adhesive that only sticks to itself.
