User Review: SteriPEN Classic
Price Paid: $150
I used the 2006 version of SteriPen (more expensive than the end-2006 version, but both rated to work the same) for two months in Nepal in fall 2006, and it worked faultlessly for the whole period -- about 200 liters for myself, and a couple other people for the first few weeks. With rechargeable NiMH batteries I purified between 50 and 60 liters per charge (of four AA batteries).
Unlike other reviewers, I found no problem with the unit at low temperatures; it worked fine -- again, with NiMH batteries -- at well below freezing. I have trekked in Nepal before and was elated this time not to have to use iodine or chlorine or other chemicals that make water taste bad. The SteriPen is far more convenient than pump filters I have used, especially when the pump filters clog and need to be cleaned.
Online research showed me that independent testing by the University of Michigan showed SteriPen to be fully effective in killing everything -- including viruses -- in 60 seconds, yet the unit is set for 90 seconds (for treating a full liter).