Pack Fit Fit is everything. Our guides agree: features, pack size and how well you pack are all secondary to fit. Torso Length Pack sizes are typically identified as Small, Medium, Large or S/M, M/L, etc. Most packs, aside from daypacks, are offered in multiple sizes to accurately fit a variety of torso lengths. Your torso length is the distance (in inches) between your C7 vertebrae and your iliac crest. Once you measure your torso length in inches, compare this measurement to the manufacturer\'s sizing chart to determine what size pack is best for you. Hip Belt and Shoulder Strap Sizing Packs are sized based on torso length, but the sizes of the shoulder harness and hip belt change proportionally to pack size. In other words, a size Medium pack comes with a size Medium shoulder harness and size Medium hip belt. If you have atypical measurements (i.e. long torso and small waist, or short torso and big waist) look for a pack with a removeable hip belt and shoulder straps so you can swap them out for the correct size. The Final Test Once you\'ve sized your pack, the final checkoff for fit is to load it up and take it for a test drive. Women\'s Specific Designs Some packs are designed specifically for women. Common features found in women\'s packs include shorter torso lengths, narrower hip belts, and shoulder straps shaped to better fit a woman\'s physique. Women\'s packs tend to be slightly scaled down in size from their male counterparts, so make sure your pack still fits the volume requirements you will need.