Teton Oasis Hydration Backpack – Lightweight Water Pack with Bladder for Hiking, Running, Cycling, Biking – 18L/22L Sizes – Sewn-in Rain Cover – Fits Men and WomenSTAY HYDRATED ON THE GO: Lightweight hydration backpack with 2L water bladder keeps you refreshed while hiking, running, cycling, or biking. Insulated bladder pocket helps keep water cold for hours. 18L 22L of organized storage. 2 LITER WATER BLADDER INCLUDED: Durable, kink free sip tube and push lock cushioned bite valve ensure smooth drinking. Wide 2" opening makes adding ice and cleaning easy. Leakproof design built for long hikes, runs, and bike