Survival kit

These filters stop bacteria and protozoa, such as E. coli, salmonella, giardia and cryptosporidium. Viruses are smaller and pass through most filters. For those, use tablets or a UV purifier.

With a straw, you drink straight from the source: it’s the lightest and simplest option. With a squeeze bottle, you first fill a pouch and squeeze the water into your own bottle, so you can take it with you and boil it. For trips, the bottle is more practical.

It varies greatly by type, from a few thousand to tens of thousands of litres. The capacity is listed on the product page. A filter that slows down is usually clogged, not worn out: backflushing often helps.

No. None of these filters removes salt from water. You need a desalination system for that, and we do not sell one.

Usually a combination of fire-making gear, cutting tools and small accessories in a tin or bag. The exact contents vary by brand, so check the product page. Many people prefer to put their own kit together around a filter and a firesteel.

A way to get drinking water. You can last a long time without food, but not without water. A filter straw weighs next to nothing and fits in any jacket pocket.