In the "active skill" fields : O means open skill slot, X mean closed skill slot
In the "skill slot" fields : "Numb." is the number of squares appearing in the upper right grid of the armor screen, while "Link." means if they are linked altogether or not
The attributes are as follow : Defense, Absorb and Weakness.
It's pointless to specify where to obtain these armors, you get'em either by craftin' 'em (if you found the books that allows you to make 'em) or by buyin' 'em at a shop.