I can't help but wonder what ya'll have to say about the "First Need" water purifier (filter?) by General Ecology. I've seen this particular model on the shelf at REI. It comes with a small bottle of blue dye, and you're supposed to run a drop of dye through the filter prior to drinking the water to make sure that the blue dye gets filtered out. If the dye shows up in the water after the water's been filtered, it means that the filter is "caput." I'm not exactly sold on the "First Need" because it seems like it would be something of a hassle to perform this blue dye test everytime you need to drink some water. "Steripen" sounds like a better deal, but I don't know if I'd be willing to stake my life on it. Has anyone ever tried the steripen? I'm not exactly sure how I'm supposed to categorize the Steripen because it doesn't really purify the water of toxic chemicals and thus it cannot be called a purifier, but on the other hand, it comes with a solar charger, it's very small and compact, and it doesn't weigh very much, so maybe Steripen is the way to go when it comes to water purification gadgets.