The Osprey Men's Siskin 8 Hydration Pack is a high-performing mountain biking pack that provides stability and comfort on the gnarliest of trails, that allows you to bring just what you need, and nothing more on your ride. Enjoy the direct-access zip path leads to an included 2.5-liter reservoir, and a U-zip main compartment opens wide to stuff a spare tube, flat repair tools, and your favorite snacks inside. The mesh-covered foam back-panel offers ventilation and allows for lively movement while keeping your pack close to your body, even when you're riding loose. The front of the pack features a LidLock attachment point for a standard-size helmet, while side compression straps expand to fit a full-face helmet. When a pack that holds only water is too small and a pack that holds everything is too big, the Osprey Men's Siskin 8 Hydration Pack is just right.