... -400, WS-500 Manuel and argon welding machine1Advanced inverter technology, a machine for TIG and manual metal arc weldi2.Automatic compensation for voltage fluctuations ... stability, fast dynamic response, low spatter,good weld appearance4.Stable and reliable, energy efficient, small size, light weight5. Unique regulatory ... water flow (L/min) cooling 1L/min WS-400 Manuel and argon welding machine