The MSR Guardian Purifier is one of the safest options around for purifying filthy water. No matter where you are the Guardian will purify upto 10,000litres of water without the need for chemicals, bulbs or batteries to ensure you can stay hydrated. It uses a simple pump action to work a patent-pending system that self-cleans with each stroke which eliminates the need to ever backflush or filter scrub to maintain flow. Working to purify 2.5L per minute it will ensure you and your team have clean and sufficient drinking water from even the dirtiest of water sources to keep you going through the task at hand.