Six Moon Design Fusion spine length

The length to the back of the spine at the attachment point is 22 inches. The length of the actual strap can be extended about 2 more inches in length by raising the velcro attachment point. This is pretty secure. Problem is if you have any chest at all the straps are pretty short.

I measure 21 3/4 inches from bottom of hip belt to the load lifters on my Fusion 65. I am 6'6" and my torso length is 21" and I have it set to what I believe is the max length and find it very secure. The pack is not resting on my shoulders when the pack is pulled tight to my back (maybe 1-1.5 inches of lift). I agree with the second commenter that if you are barrel chested and long lengthed you may find issue with the relatively short shoulder strap length. It is right on the edge for me – it would have been nice if SMD offered a large size in this regard. If this is a future option I would definitely look into changing out my shoulder strap system.