The Printfile 357BXW25 has an exclusive thin backing to allow high clarity so that you can view your negatives without removing or handling them.The strong continuous seams prevent negative hang upThe Printfile 357BXW25 is made of archival quality polyethylene, which enables long-term storageIt has 3 mil top sheet and 1.8 mil bottom sheetIt holds seven 35mm strips of 6 frames and measures 915/16" x 115/8" (W x H)