@@ The choice of museums for clarity and support. L-Velopes? are manufactured from archival quality crystal clear Mylar? polyester. Heat sealing prevents any harmful adhesives from damaging the contents. L-Velopes? support their contents and protect them from stress, dirt, fingerprints and atmospheric pollutants. Two adjacent sides open so artwork slides safely into place. Flaps then fold over to make a non-adhesive seal. The process is easily reversible, leaving the artwork in its original, pristine condition and the L-Velope? ready to reuse.