The Osprey® Moki Hydration Biking Backpack is perfect for packing a light layer, hydration, and snacks on a short hike or bike ride. This Osprey kids bike backpack is outfitted with a hydration pack, including a quick-zip reservoir sleeve and Hydraulics™ LT 1.5L reservoir. It has front panel access to the main compartment, a front shove-it pocket, a small external zippered pocket. There's even a blinker light attachment on the back for better night visibility. The Osprey Packs Moki Hydration Biking Backpack is made of durable nylon ripstop with a 1.5L capacity. 210D Poly Triple Diamond Ripstop - Main. Weight: 0.44 lbs. Dimensions: 13"H x 8"W x 3"D. Imported.