Mix with clean, potable water to create a preserved, buffered, saline solutionSuperior to tap water for emergency eyecareCapacity Suitable for Porta Stream® II eyewash stationsEye saline solution is a liquid and freezes easily when shipped during the cold weather season. If solution freezes in your personal eyewash bottles, you can thaw and then shake vigorously to mix salts back in and then it is ready to use. If the bottle collapses after being defrosted, that is an indication that there is a pin hole from expanding when frozen, in this case you must discard.