'Breastplates' in the Bible

and they had breastplates like iron breastplates, and the sound of their wings [was] like the sound of many {horse-drawn chariots} running into battle.

And in this way I saw the horses in the vision, and those seated on them, who had fiery [red] and hyacinth-colored and sulphurous [yellow] breastplates, and the heads of the horses [were] like the heads of lions, and out of their mouths came fire and smoke and sulphur.