The Alter Ego system—available in two styles, Outdoor and Globetrotter—filters out all kinds of nasty contaminants that others don't even take into consideration. The $64.99 Outdoor model has a 99.99% contaminant reduction rate while the $74.99 Globetrotter model has a mind-boggling 99.9999% rate—so you can feel safe dipping your bottle into whatever water source you can find.
As an added bonus, when you pick up one of these bad boys, part of the proceeds goes to ONE DROP, an international non-profit that develops sustainable water access products around the world. So you can share the hydrated love. Win-win.