Those familiar with the Osprey lineup may be interested in knowing that the Tempest is essentially a women's version of the super popular Talon: it differs by havingits back length and carrying straps redone to best suit a woman's body. - Carrying straps and back panel conform to your body shape, for unparallelled carrying comfort - Adjustable back length - Elastic front panel pocket - Elastic side pockets - Compression straps - Stow on the go system: easy use of hiking pole holders - Hydration bladder compartment - AirScape back panel offers great ventilation - Chest strap with safety whistle in its buckle - Compression straps at sides - Led blinker holder - Ice axe loop (some of us just won't leave home without one...) - *Check the extra image to see how to measure your back* - measure the distance between the most protruding neck vertebra and the height of the iliac crest - S/M is recommended for back lengths between 34 and 43 cm - L/XL is recommended for back lengths between 40.6