Osprey says about the Seral 4
For riders looking for a low-profile lumbar pack with integrated hydration, 4-litre Seral is the perfect trail companion. This slim waist pack features the next-gen 1.5-litre Hydraulics™ reservoir with high-strength magnetic coupling for improved hose management even in rough terrain and enough storage capacity for ride essentials, such as a spare tube, CO2 and multi-tool and, of course, snacks.