The Print File 35 7B (25 pack) holds seven 35mm strips of 5 frames, 35 frames total and contact prints on 8"x10" paper. It features exclusive thin backing coupled with high clarity, which allows you to make quality contact sheets without removing or handling negatives. These sleeves provide strong continuous seams which prevent negative hang up. The top sheet is 3 mil and the bottom sheet is 1.8 mil. They are made of archival quality polyethylene and safe for long term storage. PAT passed.