Platypus GravityWorks 4.0L Filter System

The GravityWorks 4.0L Filter System is pretty dang easy to operate, and there are plenty of devotees who can't get enough of the world's simplest water filtration system. Just fill one of the Platy Zip bags with water, place it above the empty bag, open the hose clamp, and let gravity do the rest. In 2.5 minutes, you'll have four liters of clean water, and if camp is far away, fill the other bag to carry back with you. Open the hose clamp to dispense water, and shut it to stop the flow. To clean, simply reverse the bags for four seconds, running water through the filter in reverse. That's seriously it.

, Gravity filtration system ensures effortless filtering while backpacking, Two 2L bags for dirty water suspended over one another for auto filtration, Filters 4L in 2.5 minutes without any need for pumping, Shut-off valve eases control when filling up water bottles, Reverse-flush cleaning takes four seconds