I noticed there is an option of 2 sizes, Small/Medium. What particular area of the pack does it refer, presumably the 85 refers to litre capacity?
SunnySports S The difference in sizes is for the torso fit range and the capacity. The fit range for the Small (14 in.-17 in.) and the Medium ( 16 in.-19 in.). Yes, the 85 refers to the capacity of the pack, butonly on the [Medium] 5200 in3 (85 liters) but the small has a drop less at [Small] 4880 in3 (80 liters). I hope that helps. Stay safe and have fun out there! Neal