[MrB]

It is a filter/purifier. From my understanding, it filters microbes, etc, as well. They use (expensive, but cleanable) ceramic filters. The more elements, the faster the water flow.

http://www.bigberkeywaterfilters.com/berkey-filter-systems-c-1

[nomad]

I see,I`ve already purchased a small hand pumped ceramic filtered purifier,but if I can raise the funds,one of these may fit the bill.