Protect and preserve your precious photos and documents with this set of 40 high-clarity, 3 mil polyester sleeves. Many plastic items are made from polyvinyl chloride (PVC or vinyl) which contains a chemical to make the it more flexible. The bad thing is that this chemical will breakdown over a short period of time-causing damage to your items you meant to protect. Our polyester sleeves are chemically inert and crystal-clear. It uses inherent static electricty to keep items from shifting in the sleeve. Keep your precious memories safe for generations with products from Gaylord Archival. Passed P.A.T.