"Heals me and repairs the armor even while I'm in combat." Tony shrugged. "I'm not sure I won't age. Even if it repairs my body whenever, eventually the nano tech will stop working, just like any other tech. Everything wears out in its own time." Though he might end up looking forty still when he was fifty or sixty. "The electromagnet interferes with the tech. You know how you stick a magnet too close to a computer or floppy disk? It's the equivalent."