1.0- 1.6 mm. The tungsten needle can be 1.6 mm, 1.6mm or less, 0.8mm or 0.5mm, but the current is selected according to your thickness and structure, and the current determines the choice of tungsten electrode diameter. In general, 1.0- 1.6mm diameter black needle is the most practical. Tungsten needle is a slender tungsten product, made of pure tungsten or tungsten alloy. It can be used as electrode material in argon arc welding technology and also as instrument probe. It has the advantages of high temperature resistance and good electrical conductivity.