This acid-free mounting board carries a pH neutral, pressure-activated adhesive. It permits easy positioning and repositioning until firm pressure is applied with a burnisher or press, forming a permanent bond. Perfect Mount board is the perfect choice for adhesive-resistant items such as photographs, varnished posters, prints on gloss paper, and laminated materials. It's easy to use, and there are no sprays or wet pastes to deal with. Double thickness boards are 1/8" thick. Foam center boards are 3/16" thick and comply with government regulations for environmental safety.