If your preference is for an off-the-back hydration solution instead of an over-the-shoulder pack, the Osprey Seral with 1.5L Reservoir Hydration Lumbar Pack is for you. There are a lot of luxuries we can go without on a mountain bike ride, but water isn't one of them. The Seral lumbar pack is designed to carry an included 1.5-liter lumbar reservoir with a magnetic bite valve that attaches to the hipbelt for easy access while you pedal. Compression straps pull the pack into your lower back and wrap around your hips for supreme stability, even over technical terrain. Some lumbar packs have a tendency to creep around while you ride— Osprey promises this one won't. A zippered main compartment is big enough for a spare tube, patch kit, mini pump, tire lever, and multi-tool, while hipbelt pockets can store your keys, sunscreen, phone, and trail snacks.