Aquatabs water purification tablets quickly and reliably purify drinking water on-demand. They&';re effective against viruses, bacteria and Giardia cysts, providing safe drinking water in just 30 minutes. Ideal for ultralight backcountry travel, they&';re also great for international travel and domestic emergency use. And because they&';re individually packaged, they travel well, making the ideal emergency back-up to any microfilter.