Hand-held Spot welder Welding Machine Weld Laptop Battery Button Battery Pack 220V Welding traces are clear, small spark, without any phenomenon of depression and flow of liquid. The control circuit is using SCR discharge pulse circuits and digital program to control circuit. Pressure of solder pin and distance between two pins can be adjusted independently. It can be self-diagnostic maintenance. Can weld: laptop battery, mobile phone battery, button battery, battery pack and 18650 battery etc.