You are buying 16 Ounces (by weight) of Printed Circuit Board Etchant. The item is in TWO 8 Fluid Ounce (by volume) Polypropylene bottles. The active ingredient in our Etchant is Ammonium Persulfate ((NH4)2S2O8). SUGGESTED USE Mix with water to make your own etching solution. 4 Ounces makes 16 Fluid Ounces (448 mL) of Solution. 16 Fluid Ounces of Solution etches 280 square inches of circuit board. This etchant remains transparent as it dissolves the copper from the board so you can monitor the etching process (unlike Ferric Chloride solution, which turns black). No heating or agitation required. Etching time is 5-15 minutes at room temperature. Spent solution can be neutralized with Baking Soda (Sodium Bicarbonate). The spent solution contains Copper Sulfate. Bottles are made of sturdy polypropylene. The square, “space-saver” shape ensures that the bottles fit snugly on a shelf. The wide mouth makes for easy dispensing and stackability. To ensure a spill-free journey, the screw tops are heat-sealed and the bottles are sealed in plastic.