If your looking for a water filter, the Katadyn Pocket Microfilter is a very good filter with a .2 micron rating which will filter out 1 micron more bugs out of the water than the hiker, but I would get a filter that also has a carbon filter as well like the Katadyn Combi. The carbon helps take out chemicals that are in today's waters like pesticides, petroleum products etc.. The Katadyn Combi gives you the the capability of the Pocket but with carbon granules for chemicals and pesticides and it's cheaper. You will still need to boil the water for virus bellow the .2 micron level or use a steripen, miox or other types of purifiers. There are purifier filters out there but I think the Katadyn filters will last longer in the field. If you just want something for short camping trips then the water bottle purifiers would work and you wouldn't have to boil the water but they have a very short filter life. I have a Katadyn Combi and a steripen and the combo works great for what I do--> Chemicals and viruses.


Katadyn Pocket Microfilter = $200
.2 micron filter 13000 gallons used by swiss army and built solid and highly recommended between the two

Katadyn Hiker Microfilter = $60
.3 micron filter 200 gallons
Reviews for the Hiker (complaints about handles and pumps breaking in the field
http://www.trailspace.com/gear/katadyn/hiker/

Katadyn Combi =$139.95
.2 micron filter 13000 gallons plus replaceable carbon granules for pesticides,chemicals, etc..