Simple, compact, and versatile—the Sawyer MINI Water Filtration System is all that and more. First off, it's aptly named; the filter itself is lightweight and fits in the palm of your hand. Next, you can use it with the included 16-ounce bag, a water bottle, a straw, or—my favorite—inline with your water bladder. Finally, it's long-lasting; the filter is rated to filter 100,000 gallons. Need we say more? Available online; $25.