Gravity Works is a unique filtration system that easily and quickly filters out the water in the nature and cleans it from all the harmful organs. Feel free to drink even in places where no drinking water is available. With a high bag volume and a flow rate of about 1.5l / min, you can filter out enough water in a short time even for other needs such as bathing or cooking. The microfilter meets EPA and NSF standards for the removal of bacteria and protozoa and traps impurities up to 0.2 microns.The package includes two 2 l bags, a filter hose, a bottle adapter with a closure, a universal bottle adapter and a package.