Stay hydrated while you're crushing trails during races or daily workouts with the super light and streamlined Osprey Rev 1. 5 Hydration Pack. Osprey entered the ultralight game this year with its Rev series backpacks, and the Rev 1. 5 is the smallest of the lot. The backpack comes with an integrated, lightweight 1. 5 liter reservoir that's specially designed to prevent water from sloshing around while you're bouncing up and down the trail, and the backpack itself is designed to fit snugly and follow your movements to prevent irritating jiggling and uncomfortable chafing. Not just one, but two sternum straps keep the pack securely in place, and can be adjusted to your preferred position. One includes a magnet that conveniently holds the drinking tube's bite valve so you can quickly sip and then get the drinking tube out of the way. Two pockets one on each shoulder strap hold energy gels and your cell phone. The Rev 1. 5 is designed to sit higher on your back, and doesn't use a hip belt at all since the shoulder harness supports the entire load. With the Rev 1. 5 on your back, you won't ever have to worry about your hydration pack slowing you down during a race or fast moving training session again it'll pretty much just feel like part of your back.