.030 - No need for shielding gas. This flux cored wire can be used in mig welding that does not require the use of shielding gasses. Type E71-T-GS. A flux core welding wire designed to weld carbon steel. The operator appeal, bead appearance and spatter is not equal to a gas shielded product, but the benefit of not having to use gas makes this product extremely popular. Excellent for use on lap and fillet welds on thin guage galvanized and mild steel in all welding positions. Operates on DC straight polarity.