Where a thread, a bore and a micron rating decide everything

The cooking and water kit, and what has to match

This is the part of the kit where compatibility is not a detail. A stove takes one valve and not another, a filter screws onto one bottle thread and not another, and a cartridge that fits nothing is a cartridge you carry home. Every figure on these pages is reported as the manufacturer publishes it — and where a filter is concerned, what its maker declares it reduces is all that is reported: whether any source may be drunk is a question for that maker and for the local authorities.