I can get these for $19. http://aquamira.com/military/frontier-pro-filter-system

Capacity is 50 Gals, dry weight 2 oz.  I was thinking about these for  short-term/duration use in GHBs, possibly in conjunction with tablets or similar.

Does anyone have any experience with these gadgets?

I found this review, which was carefully done by someone used to the outdoors. http://www.backpackgeartest.org/reviews/Water%20Treatment/Filters/Aquamira%20Frontier%20Pro%20Filter/Test%20Report%20by%20Kurt%20Papke/

Even though I found a place to get the Frontier Pro for $14, it seems that the thing only works well attached to a "squeeze" type bladder, so that cost has to be figured into the equation.  Another point is that like most filters, the quality of the pre-filter has a big effect on the main filter's life.  The pre-filters included with this unit are pretty coarse, and so the filter clogs up fairly soon (and irreparably so) if used to filter cloudy water.  so, a good pre-filter with cleanable elements is needed.

What I did find out, is that the "head" of the water going into a gravity filter makes a huge difference in the rate of flow and time required to obtain a given volume of product.  This guy http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=10012 used a long hose to connect his dirty water bladder (raised overhead with a line) to his ground-level filter, and found the flow of filtered water was greatly increased

I have no personal experience with that one but have a lot of confidence in their products.

I've used one of their squeeze bottles for years and used it in water I know for sure was contaminated with no ill effects.  

Tj

I concur.  Please gather together links to your important hydration threads into one single thread, and I will non archive the several threads.

Much better if you could make a summary thread all by itself.