Since you are, guys, talking about filters and water, a question:
What do you do when you travel by plane? What do you drink in the plane? (there is no boiled water there).
I'm planning to go on a trip for a couple of a day to a different city, what do I drink while I'm there. I won't be able to have my tea-pot to boil my water with me? What do you do?
And when you go out, all water is tap water, so what do you drink at a restaurant?