Bests & Worsts Reviews from Amazon

Useless in most any survival situation. The instructions, printed in almost unreadably small letters, read "upon first use or anytime the filter is dry, uncap both ends and stand it up in safe water (keeping mouthpiece out of water and dry) for 20 seconds to allow water to prime filter." If potable water is required just to prime the LifeStraw, it's very unlikely you'll have potable water on hand. After all, you're using the LifeStraw to filter contaminated water BECAUSE YOU'RE OUT OF WATER!!!