I and my friends really like our Katadyne pump filter. I don't know the model number. It's about 8 to 10 inches tall and not too big around, maybe two to three inches. It works beautifully, we've been using it for about 5 years. One filter will filter a lot of water. I personally have the same water filter at home in my emergency gear (in case of earthquakes, etc). In a addition to our Katadyne, each one of my friends and I carry our own Bota water bottle with a built in filter in case we get separated. None of us have ever experienced Giardia or any other type of micro-organism / bacteria. (frankly, I don't know what Giardia is, I'm not even sure I'm spelling it correctly, all I do know is that it can mess with your system biologically). Guess I should head straight for Wikipedia to look up this little varmint. We picked up our Katadyne at REI. Bota bottles are probably available at REI; however we got ours online from Sierra Trading Post. Adventure 16 probably has all these water purifyng devices too and don't forget to check out Campmor.com, I love Campmor, I've been shopping with them for about 30+ years now.
