NET
15 “Look, I am making you like a sharp threshing sledge, new and double-edged. You will thresh the mountains and crush them; you will make the hills like straw.
Darby
15 Behold, I have made of thee a new sharp threshing instrument having double teeth: thou shalt thresh and beat small the mountains, and shalt make the hills as chaff;
KJV
15 Behold, I will make thee a new sharp threshing instrument having teeth: thou shalt thresh the mountains, and beat [them] small, and shalt make the hills as chaff.