LifeStraws are great backpack staples for hiking, or nice gifts for the outdoorsmen in your life. They’ve been ping ponging between about $14 and about $20 lately, but it’s currently on the low end of that price range, if you need to pick up more to give as gifts.
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.