Contains a buffered saline solution that is sterile and superior to tap water for emergency eye careBlow-Fill-Seal (BFS) bottle is tamper resistant and maintains the sterility and integrity of the eyewashEasy to remove and open in emergency situationsDoes 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.