The Smead Poly Envelope is designed to protect important documents long-term with its acid-free, archival quality material. Made from heavy-duty, PVC-free polypropylene, it resists tears and repels moisture, ensuring your papers remain safe. These tough, side-loading envelopes feature 1-1/4 expanding gussets that can hold more than 200 sheets of paper and come with a hook-and-loop closure for easy opening and closing.