The only British canteen with the filter on the cap, "that I know" is the one made by pre-mac.<br><br>http://www.pre-mac.com/<br><br>Some of these were on uscav as far as I know. It is not a new product but was only being used by some specialists like the SAS or The British Civil Defence Rapid Intervention team for more than 10 years.<br><br>We have been using it on the field and supplied water for the team in two earthquakes and some flood intervention without any problem (you do not even want to think about the sort of water dealt with). I do not think about any substitute for the product I have been using. Just my personel thoughts though.<br><br>Burak<br>Istanbul