... of furniture, vehicle, electric power, construction, conduit.... WS series IGBT invert DC TIG welderItem\ModelWS-315WS-400WS-500WS-630DC ... ModeFanTIG Arc StartingHF Arc startingAdvanced Air Feeding(S)0.30.30.30.3Delayed Air Shutting(S)2222Overheat ProtectionYesYesYesYesUndervoltage/ ... descending current, auto crater filling, gas pre-flow, gas post-flow function.e). Advanced IGBT-20KHzTM dual inverter ...