I just got back from a 3-day backpacking trip in Canyonlands National Park where I got a chance to put one of my recent gear purchases to the test. We carrierd our water in but were almost out by second day. Luckily, I brought my Aquamira Frontier Pro water filter. I threw it in my personal kit "just in case" and it was a good thing that I did. We filtered 5 liters of water and haulled it back to our camp with plenty to spare. Without it, we would have been out of luck. It's light, compact, and cheap; making it the perfect backup filter. Check out the video (note my beloved Mountainsmith Ghost in the background):
While it's not the most potent filter, it serves the purpose well for emergencies and the taste is pretty good! Here are the specs:
-Filter capacity: Up to 50 gallons (190 L)
-Weight: 2 oz
-Dimensions (approx.): 6" (length) x 1" (diameter)
Also, I've discovered that you can remove the bite valve which gets me to thinking that I could experiment with an inline gravity filter setup. Hmmmm....