Lindner Philatelic Sleeves are made from crystal clear plastic film free of acids and chemical softeners (unplasticized vinyl). The two long sides and one short side are sealed with one short side left open. Sold in packs of 50 sleeves. Film Thickness: 0.10mm Size: US Covers (6 11/16 x 3 15/16 inches (170 x 100mm))