The Sawyer Mini is an incredible water filtration system. I have used about every type of water purification out there and the Sawyer Mini works the best for my needs. I like that it screws on to their water pouches, store-bought water bottles, etc. it can be used as an inline filter for a bladder system or as a straw with the included flexible straw.
The system also comes with a large syringe for backflow cleaning of the filter. The company says it is good for 100,000 gallons of purified water. The filter removes all the bad guys except for virus.