50 E. Gerber Mylites 2 Mil Mylar Super Gold Comic Book Sleeves 800M2 Protection from Humidity Protection from Volatile poly bag breakdown Protection from Acid migration Protection from Oxygen decomposition Protection from Insects 50 E. Gerber Full Back GOLD SIZE 42pt Acid Free Backing Boards 758FB These are the highest quality boards found anywhere! At 42-Mil, these provide greater protection than regular backing boards! Made from 100% acid-free, virgin wood, cellular fiber, 42 mil. thick cardboard. Contains a 3% alkaline buffer and a pH content of 8.0-8.5. Sold in packs of 50; Measures 7 5/8" x 10 1/2". White on one side and cream on other