The Session 16L bike hydration backpack is a full-featured pack combining the cooling comfort of a breathable back panel with airy shoulder straps. This narrow, lightweight pack features a larger 3-liter vertical hydration reservoir with a bite valve. The Session is a do-it-all bike pack to keep you out all day on the trails. Details: 3L/100oz Hydrapak reservoir, phaser bite valve, breathable air flow backpanel and shoulder straps, full face or trail helmet carry, fleece lined sunglass pocket, internal organizer pockets, safety light attachment, integrated rescue whistle-sternum strap, limited lifetime warranty. If your bag gets dirty, Dakine recommend hand washing with mild soap (like Nikwax Tech Wash), cold water and a soft bristle brush. If hand washing is not going to do the trick, use a front loader washing machine. To ensure your backpack doesn't get tangled, place inside a pillowcase or mesh bag before washing. Always use cold water, mild soap and run on a gentle cycle. Never bleach your pack. Hang to dry in a warm but shady place, ensuring both inside and out are dry before storing. Dimensions: 976 cubic inches (16 liters), 17.5'' x 10'' x 8'' (44 x 25 x 20cm), 1.6 lbs. (.75kg). Material: Nylon, Polyester.