Copper etchant. More aggressive than persulphate alternative. Can be stored and reused. Ready to use solution designed for etching printed circuit boards and other metals. Recommended for use with M.G. Chemicals professional etching process kit and M.G. economy etching process kit. Ferric chloride (FeCl3) liquid solution phase. 1.4 specific gravity. 162.21 Molecular weight. Dark brown appearance. 106 degree C boiling point. 1.0 - 2.0 pH (5 percent by volume). 0 degree C freezing point. 100 grams/liter maximum copper holding capacity. 175-200 microinch/minute at 50 - 55 degree C etch rate. 50 - 55 degree C operating temperature. ROHS Compliant.