The Osprey Daylite Backpack is ideal for minimalist missions fast-paced hikes and travel itineraries where lightweight carrying and minimal bulk is of utmost importance. It's an ingenious add-on to larger Osprey packs specializing in carrying only the essentials when a larger pack is simply overkill. Hydration-compatibility means it'll accept an Osprey Hydraulics reservoir (not included) when you're walking long distances ascending high altitudes or dealing with hot climates.