What Our Gearhead(R) Experts Are Saying: "I love how the Seral 7 keeps everything low and stable-it's my go-to when I want freedom to move without a full pack. The lumbar reservoir works perfectly, and the compression straps pull it snug so it doesn't bounce, even on rowdy descents." For riders who want hydration without the bulk of a backpack, the Osprey Seral 7L Hydration Pack delivers streamlined performance and rock-solid stability. Designed with a lumbar-style carry, it keeps weight low and centered, improving balance and comfort through rough terrain. The AirScape(TM) backpanel's ridged foam construction channels air to keep us cool, while the contoured lumbar wrap and ErgoPull hipbelt system lock in a secure fit. A 1. 5-liter Hydraulics(TM) Lumbar Reservoir provides quick hydration access via a magnetic hipbelt hose attachment, and the zippered main compartment neatly stows a spare tube, tools, and snacks. Dual hipbelt pockets, reflective details, and compression straps complete the setup, ensuring every ride feels smooth, stable, and efficient. Built with recycled, bluesign(R)-approved materials and PFAS-free DWR, the Seral 7 is the ideal blend of sustainability, stability, and trail performance.