... 3. Inner wire feeder structure keeps the welder be integrated. 4. Work in high efficiency with good welding quality ... alloy steel, and Cr-Mo high strength steel copper. Control system: PWM control technology, constant current characteristic is good, high energy; ... , weld seam Z shape is beautiful. Improve the protection system: Undervoltage, overvoltage, overcurrent, oerload, to ensure welding safety ...