With a vest-like fit, the Dyna 1.5 helps you keep your hydration levels high. The Dyna is the best fit for most women. For men, Osprey makes the Duro. - INcluded: 1.5 liter Hydraulics LT bladder, hose and valve - Stow-on-the-go pole holders can be used on the fly, that is without a need for taking the pack off - Front stretch pocket - Stretch side pockets - Weights and measurements per size: - S: 350 g, dimensions 26 x 37 x 13 cm, for chest circumferences between 6575 cm - M: 370 g, dimensions 31 x 37 x 13 cm, for chest circumferences between 7590 cm - L: 400 g, dimensions 36 x 37 x 13 cm, for chest circumferences between 90105 cm