OSPREY SIZE AND FIT
Many Osprey packs are available in multiple sizes to fit a range of torso lengths. To determine torso measurement, use an Osprey Pack Sizer. This measurement starts at the iliac crest, which is the top of your hipbones on the side of your body that acts like a shelf. From this point, measure to the C7 vertebra, the knobby bone at the base of your neck when you put your head down. Reference the torso length to match the correct pack size.
Osprey Xenith, Xena, Aether, and Ariel packs offer interchangeable shoulder harnesses. Osprey Atmos and Aura offer adjustable harnesses. Harness sizing usually corresponds to pack size. A properly fit harness should terminate 2" to 3" beneath the armpit when at the proper torso length. The webbing should not touch the side of the body below the padding.
Osprey Xenith, Xena, Aether, Ariel and Variant series packs offer interchangeable hipbelts. To determine hipbelt size, measure around the hips, at the iliac crest, not the waist. The padded portion should wrap well around the hips, leaving a gap of 3" to 6" between the tips of both hip pads when securely tightened. Refer to the tables provided below: