Elmer's (Hunt Bienfang) 32in.x40in.x3/16in Black Acid Free Foam Board - 25 Pack

This specialty Foam Board is totally acid-free. This product features facing paper with a ph between 7.7 and 8.5. It's also made with a calcium carbonate buffer that provides many years of protection against pollutants that cause paper to become weak, brittle or yellow with age.