'Breastplates' in the Bible

They had breastplates (scales) like breastplates made of iron; and the [whirring] noise of their wings was like the [thunderous] noise of countless horse-drawn chariots charging [at full speed] into battle.

And this is how I saw the horses and their riders in my vision: the riders had breastplates [the color] of fire and of hyacinth (sapphire blue) and of brimstone (yellow); and the heads of the horses looked like the heads of lions; and from out of their mouths came fire and smoke and brimstone (burning sulfur).