.023" STEEL MIG WIRE--RL/10-LBS ER70S-6 mild steel MIG welding wire is a high strength mild steel MIG wire. Ideal for auto body repair and fabrication on most ferrous metals. Contains a high level of manganese and silicon for a superior weld, even on rusty, dirty steel. Produces a smooth bead which requires less grinding. Not recommended for aluminum engines. Yellow color coding on label.