Features: Adopt thick copper bar, help enhance the working efficiency, and suitable for long service time. Integrated design, beautiful and neat, with fine heat radiation effect. There are dual springs on the handle, each welding pen can expand and contract independently. Built-in limit switch, one hand operation, do not need foot pedal. With comfortable hand feelings, can support long time use, stable and reliable, wear resistant and effort saving. Suitable for 18650 battery spot welding machine. Comes with one connecting cable for connecting spot welding pen to spot welding machine. Note: please connect to 12 V external power source.