The BCW 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 treasury comic bags to protect and store your collectible comics. Certified Acid Free – Independent Lab Tested. Use with BCW Treasury Comic Bags. Dimensions: 10 1/4″ x 13 1/2″.