I have not yet tested frequently the Water Straw, but in applications up to speed with Bach and river water it worked. However, the processing is rather poor. Even in the original packaging, the plastic wool was not packed properly inside and stuck out on the sides. The screw caps were initially quite loose, so that you only had to correct again all screw caps and content prior to use, but this was not mentioned in the manual. I can not judge about the filtering capabilities and wants the 30 Euro unit also not waste for testing purposes. Right now I use the Water Straw as an alternative to Wasserentkeimungspillen.
The description on Amazon seems to be created by Google translation because of gibberish is barely legible and makes little sense partly.
