The company's products - copper iron reagent (alias: N-nitrosobenzoquinone ammonium salt, copper iron spirit), is non-benzene. Cadmium. Lead. Mercury. Hexavalent chromium products. White or milk scaly crystal, easy Soluble in water and alcohol, long-term color darkening, usually put a small amount of paper (or cloth) wrapped ammonium carbonate as a stabilizer in the bottle.