LifeStraws are great backpack staples for hiking, or nice gifts for the outdoorsmen in your life. And right now, they’re just $15, which is about as cheap as you’re likely to see them, with a few short-lived exceptions.

If you aren’t familiar, these allow you to sip directly from basically any source of fresh water you find in nature, and the filters will catch 99.9999% of bacteria, and 99.9% of parasites. That could come in handy during camping trips, or as you cling to life in a future post-nuclear hellscape.