Check the listing for details. 1ness Water Purification Drops Citric Kit, 2 Ounce Plastic, 4-Pack. Condition: New. Listed at 43.99 USD. 4 Pack - 1Ness® Water Purification Drops are essential for any emergency kit. They are great for camping, hiking, travel or any other immediate situation. The two-bottle set contains Sodium Chlorite and Citric Acid. When mixed together, they make Chlorine Dioxide, a powerful neutralizer. This powerful substance disinfects and makes any water source safe for drinking. It is compliant with FDA standards and is recommended by the CDC and the EPA guidelines for safe drinking water. To use: Simply mix 3 to 5 drops of PART A (Sodium Chlorite) with an equal amount of drops of PART B (Citric Acid) in a shot glass or another small, plastic or glass container. Wait for 30 seconds. Then add this mixture to any water source. 3-5 drops from each bottle will purify up to one US gallon of water.