'Breastplates' in the Bible

And they had breastplates like iron, and the sound of their wings was as the sound of carriages, like an army of horses rushing to the fight.

And so I saw the horses in the vision, and those who were seated on them, having breastplates of fire and glass and of burning stone: and the heads of the horses were as the heads of lions; and out of their mouths came fire and smoke and a smell of burning.