Platypus GravityWorks 2.0L Filter Bottle System Bottle Kit: Minimalist setup uses a Universal Bottle Adapter to connect the system directly to an existing water bottle or reservoir* No pumping: Just fill the dirty reservoir, hang it, and let gravity do the hard work. Fast: Filters up to 1.5 liters of water per minute; filter lifetime up to 1,500 liters of water. Effective: Meets all EPA & NSF guidelines for the removal of 99.9999% of bacteria and 99.9% of protozoa** Field-cleanable: Microfilter can be easily backflushed in 4 seconds to maintain filter performance.