2 mil ultra clear polypropylene Polypropylene is an inert, archival quality, PVC-Free material Ideal protections against dust and moisture during handling and storage 100 per pack Guardhouse Shield#: 636836681542. Size: 3 3/8 x 4.5 + 1" Flap. Color: Clear. Sold in Packs of 100. Case Qty: 10000 .