VARIABLE HELMET CARRY - Includes Osprey's LidLock helmet carry for traditional helmets and front panel upper compression straps for full face helmets. RESERVOIR INCLUDED - Osprey Hydraulics® LT 2.5L reservoir keeps you hydrated all day long and stores in a dedicated hydration compartment to protect pack contents from accidental spills. MOUNTAIN BIKE-FOCUSED FEATURES - Multi-pocketed tool organization and large bucket main compartment stores and protects all your essential gear. RIDE STABILITY - Our rolled, soft-edged harness contours to the upper shoulders to keep the pack close to your body and provide stability. Osprey Siskin 8 O/S Hydration Backpack