It uses four-stage filtration, removing contaminants—from large particles to extremely tiny particles effectively to ensure the safety of the water. Uses advanced Japanese activated carbon fiber filter media to ensure water safety and improve taste, providing you with high-quality water in the field. The filter adopts a 0.1-micron hollow fiber membrane to remove 99.99% of harmful substance in water. You can use the Filterstraw with water bottles or soda bottles that have a standard thread on their tops. Fill the filtered water into the bottle and take it with you anywhere you want. Filterstraw can connect to water bags or bottles, and you can enjoy clean water for yourself and with friends. There is no need for extra syringe backwashing. It eliminates extra cumbersome fittings and makes the water bag versatile.