The BCW Silver Age Comic Backer Boards are made from 24 point solid bleached sulfate, coated and buffered on one side with 3% calcium carbonate, and are precision cut to size. Use this item along with silver comic bags to protect and store your collectible comics. Certified Acid Free – Independent Lab Tested. Use with BCW Silver Poly Mylar Bags. 100 boards per pack. Dimensions: 6 7/8″ X 10 1/2″.