A copper-coated, G4Si1/ER70S-6 rod for GTAW of general structural and engineering unalloyed and low-alloyed carbon-manganese steels. Compared with OK Tigrod 12.61, OK Tigrod 12.64 has a slightly higher silicon and manganese content, which increases the weld metal strength. The high silicon content promotes low sensitivity to surface impurities and contributes to smooth, sound welds.