NET
9 They had breastplates like iron breastplates, and the sound of their wings was like the noise of many horse-drawn chariots charging into battle.
Darby
9 and they had breastplates as breastplates of iron, and the sound of their wings [was] as the sound of chariots of many horses running to war;
KJV
9 And they had breastplates, as it were breastplates of iron; and the sound of their wings [was] as the sound of chariots of many horses running to battle.