The Thule Rail 8L Hydration Pack is a mid-size pack for mountain biking. Ride aggressive without worry of this pack slipping, it hugs the body while offering breathable comfort at the back and straps. The 2.5L HydraPak reservoir holds the water, while the ReTrakt magnetic hose return system keeps the tube easily locatable when it's time for a drink. Store pads, tools, snacks, and layers for the adventure.