King James Version (KJV) - Revelation 9:9 >

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.

Berean Study Bible (BSB) - Revelation 9:9 >

They also had thoraxes like breastplates of iron, and the sound of their wings was like the roar of many horses and chariots rushing into battle.