Lineco metal edge storage boxes are acid-free, lignin-free, made with 60 point board, and designed with a drop front for ease of retrieving photographs, documents, artwork or other important and valuable items. Acid, airborne pollutants, light and dirt can attack your treasured possessions causing them to deteriorate, fade and discolor. Lineco archival storage boxes defend against these contaminants to protect your treasured possessions for generations to come.