TREN LLC (NAQWA USA) is the U.S. Importer of the NAQWA SWR-SPRING portable water filter: Light weight (only 3.5 oz.) gravity fed, compact: Russian technology; Excellent for backpacking, emergency prep, camping, hunting, first responders. Makes any water safe to drink. The NAQWA filter is not a straw-type device. It utilizes molecular cleaning technology (developed in the Russian Nuclear Technical Centers) instead of standard charcoal filtration. The safest portable water filter in the world due to its open-type construction. About 90% of portable water filters are of the closed-type. (less)