I looked at the NSF site as well. NSF only tests products submitted to it. The submitter must pay for the cost of the testing. I suspect that Steripen hasn't submitted for testing as of today.

The question I have is re viruses. Does Steripen kill viruses too? Or did I miss that on the site? If Steripen kills viruses, then it might be a really great thing to have while travelling in warm climates, superior to filters.

I don't think I'd depend on anything battery operated in a cold climate, but I suppose one could always take spare batteries, and can warm the batteries by placing them in a pouch around one's neck which will increase performance.