100 E. Gerber Mylites 2 Mil Mylar Standard Magazine Sleeves 900M2 Protection from Humidity Protection from Volatile poly bag breakdown Protection from Acid migration Protection from Oxygen decomposition Protection from Insects 100 E. Gerber Half Back Magazine Size 24pt Acid Free Backing Boards 858HB These are the highest quality boards found anywhere! At 24-Mil, these provide greater protection than regular backing boards! Made from 100% acid-free, virgin wood, cellular fiber, 24 mil. thick cardboard. Contains a 3% alkaline buffer and a pH content of 8.0-8.5. Sold in packs of 100; Measures 8 5/8" x 11 1/2". White on one side and cream on other