Delivers 3 minutes of flushing fluidOne-gallon sealed cartridges are easy to store and offer quick changes without mixing or measuringDoes not meet ANSI standard Z358.1-2009 15-minute flushing requirementEye 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.