They have iron and glass jaws, but I will say that they hyped up Conor's durability based on the fact that he could take digs from men he weight bullied. Then once he moved up he's shown more frailty. Remember Diaz was beating the daylights out of him and he doesn't have good power. He made Conor give up that submission, in fact anytime someone stands up to Conor and takes it to him has successfully made him essentially give up his back and get submitted. He's got quit in him.