What's worse than getting a flat 4 miles into the ride? Not having the proper pack or adequate hydration, that's what. The Viper 13 is here to make sure you have everything you need for a ride including a special spot to hold a bike pump and extra tubes, just in case. Equipped with Osprey's Hydraulics LT 2.5L reservoir and magnetic bite vale sternum strap clip, you'll have easy access to 2.5 liters of refreshing hydration for endless miles on the trail. The foam framesheet, mesh backpanel and BioSretch shoulder harness provide contoured support and ventilation for all day comfort. There are plenty of easy-access pockets for stashing all your essentials, including a stretchy front Shove-It pocket, which is perfect for extra layers and trail maps and a handy Lidlock helmet attachment system so you won't lose your bucket at the pub while celebrating a stellar ride with the guys.