When enchanted, P. Def. increases by 1 for A-grade armor and accessories. Starting at +4, P. Def. increases by 3 and a HP bonus is granted. Enchanting is safe up to +3, but one-piece body armor can be safely enchanted up to +4. If enchanting fails, the item will not be crystallized but the enchant value will be reset to 0. It can't be exchanged or dropped.