Which steripen type UV purifiers will work with a narrow mouthed water bottle such as a Smart 1L bottle?
Hi there @outpac94!
While many purifiers are designed to fit with wide mouth bottles, there are some that can be inserted in a narrow bottle far enough to create a seal between the "pen" and the bottle so that the bottle of water can be flipped over and the water treated.
The Katadyn Ultra Water Purifier is an example of a purifier that should work for you in this case.
Hope this helps! Additional information on water treatment can be found in our Expert Advice article about choosing a water filter or purifier!