No doubt in my mind I pick my best hiking friend Katadyn portable water filter !
This robust water filter made of heavy-duty materials is ideal for long-lasting continuous use even under extreme circumstances. The silver impregnated ceramic element is effective against bacteria and protozoa and can filter up to 50000 Liters of water with one 0.2 micron ceramic depth filter (cleanable).
wow. Now that is a very impressive filter! I was going to say something silly, like a tiny tent, but I think you win!
Oh - aren't those tiny tents just terrible ? !
I used one while camping with friends - just to try it out. They guy who owned it was one of these trendys who goes for the latest gadget, whether practical or not. We swapped tents and I tell you, never again. I can only describe it as laying inside a very slightly loosened Egyptian shroud. Horrible.