Hello burrmsp,
Depending on what your doing and budget. camping near a stream or hiking for the day and need a filter. Katyden and Sawyer are very good products. One of the best ones that I have found is www.berkeyfilters.com This product will filter streams, lakes, rivers, and stagnet water. They have a sports bottle for $32 or the Go Berkey kit for $159 that's good for travel.
Good luck and drink safe
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