Gregory Sage 45 Backpack Size Chart
  Small Medium
Torso Length (in) 16-18 18-20
Capacity (cu in) 2746 2990
Product Weight 3 lbs, 4 oz 3 lbs, 6 oz

These are general guidelines only, sizes are not guaranteed. But no worries, since at SunnySports we offer our exclusive PFF Guaranty