... :0~10sec Output AC frequency:70Hz square AC balance: 50%-90% EN Duty cycle:60% Pilot arc model:high frequency Max.welding thickness:0 ... arc,easy to fill the wire 2, small size,light weight,easy to move 3, easily switch operation modes:MMA/TIG,AC/DC ... 4, AC TIG welding for aluminum,magnesium and their alloys. 5, DC TIG welding for stainless steel,alloy steel ...