I like external frames when I am playing sherpa for the kids. Much easier to load a huge volume and still carry it comfortably. That frame does look interesting, especially the lumbar plate. I think that wings would work better. The weight of less than 3 lbs is impressive, but the weight limit is very small. And, that is probably because of the hip belt. For a hip belt to hold more weight, it is hard to get one that is lightweight itself.
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