Corrosion Intercept clear poly zip-lock bags provide effective tarnish protection for metals. When the copper color color turns black it?s time to change the intercept package. Protects item for up to three years. Provides protection from tarnish for up to three or more years. Does not leave deposits on items it protects. Nontoxic, non-abrasive, and will not scratch or harm metals or gemstones. Before placing item in pouch, be sure item is clean, dry and free of fingerprints and deposits. Size - 2" x 4" Sold as Pack of 20