Metal-edged drop-front boxes consist of a removable top and a bottom with a hinged 'drop front' panel at the long side. Made of heavyweight Archival Grade boxboard. Metal edge clamps are corrosion treated in black polyester coating with a wax-free polyester finish on the blind side. Clamps provide rigidity and high stacking strength. The lignin content is measured by the phloroglucinol test with a Kappa number of 5 or less. Made from fully bleached, high alpha cellulose pulp. It does not contain any post consumer waste recycled pulp. Paper is free of metal particles, waxes, plasticizers, residual bleach, peroxide, sulfur content is less than 0.0008% reducible sulfur. Metallic Impurities, Iron will not exceed 150 ppm and copper shall not exceed 6 ppm. No optical brightening agents are used in the pulp. Paper contains a minimum of 3% calcium carbonate (CaCO3) with a pH range 8-9.5 Alkaline or neutral sizing are used. No alum rosin or rosin sizing are used.