Riders looking for a low-profile lumbar pack with integrated hydration need look no further than the Seral 4. This slim waistpack features a 1.5-liter bladder with our updated high-strength magnetic coupling for improved hose management even in rough terrain. The Seral 4 has enough storage capacity for ride essentials, such as a spare tube, CO2 and multi-tool and, of course, snacks. Our bike-specific, angled hipbelt and compression straps provide stability and comfort by keeping the pack close to your body. This is created by a breathable airmesh wrap hipbelt that contours over the hipbone, Osprey's ErgoPull cross-body waist strap closure system that pulls the pack into the lumbar and side compression straps that pull the load close to your body, providing the most comfortable, secure and stable carry. Designed for riders who require hydration or gear storage while riding, but prefer the off-the-back carry and minimalism provided by lumbar packs. Constructed with PFC-free recycled bluesign®-approved nylon; a sustainable build that's tough and durable to endure years of riding.