This affordable pack is ideal for the trail. It contains a water bladder for staying hydrated as well as pockets for phones, snacks, and gear. The BPA-free and food-grade plastic bladder (picture an IV drip bag, not the anatomical organ) holds 2 liters of water (that’s almost 9 cups) and slides into an insulated compartment to keep it cool on hot days. Slip the pack over your shoulders and buckle around your waist for a secure fit. When you’re thirsty, grab the bladder’s hose and use it as a straw.