From the BBC:

The lightweight aluminium exoskeleton, called XOS, senses Rex's every move and instantly moves with him; it is almost like a shadow or a second skin. It is designed for agility that can match a human's, but with strength and endurance that far outweigh our abilities.

With the exoskeleton on and fully powered up, Rex can easily pull down weight of more than 90 kilos, more than he weighs.

For the army the XOS could mean quicker supply lines, or fewer injuries when soldiers need to lift heavy weights or move objects around repeatedly. Initial models would be used as workhorses, on the logistics side.

They look quite fragile, don't they? A bit of a drawback that they haven't nutted out how to power the thing either.